WP-4a: menu-bar shell, AppModel, session strip per SPEC-A2b + integration contracts

.gitignore

@@ -0,0 +1,8 @@
+.build/
+.swiftpm/
+Packages/
+*.xcodeproj
+xcuserdata/
+DerivedData/
+.DS_Store
+.netrc

Info.plist

@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleIdentifier</key>
+	<string>ai.flowmaster.shotdeck</string>
+	<key>CFBundleName</key>
+	<string>Shotdeck</string>
+	<key>CFBundleExecutable</key>
+	<string>Shotdeck</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>0.1.0</string>
+	<key>CFBundleVersion</key>
+	<string>1</string>
+	<key>LSUIElement</key>
+	<true/>
+	<key>LSMinimumSystemVersion</key>
+	<string>14.0</string>
+	<key>NSHumanReadableCopyright</key>
+	<string>Copyright © 2026 Flowmaster FZC LLC. All rights reserved.</string>
+</dict>
+</plist>

Package.swift

@@ -0,0 +1,31 @@
+// swift-tools-version: 6.0
+
+import PackageDescription
+
+let package = Package(
+    name: "Shotdeck",
+    platforms: [
+        .macOS(.v14),
+    ],
+    products: [
+        .library(name: "ShotdeckCore", targets: ["ShotdeckCore"]),
+        .executable(name: "Shotdeck", targets: ["Shotdeck"]),
+    ],
+    dependencies: [],
+    targets: [
+        .target(
+            name: "ShotdeckCore",
+            swiftSettings: [.swiftLanguageMode(.v6)]
+        ),
+        .executableTarget(
+            name: "Shotdeck",
+            dependencies: ["ShotdeckCore"],
+            swiftSettings: [.swiftLanguageMode(.v6)]
+        ),
+        .testTarget(
+            name: "ShotdeckCoreTests",
+            dependencies: ["ShotdeckCore"],
+            swiftSettings: [.swiftLanguageMode(.v6)]
+        ),
+    ]
+)

README.md

@@ -1,3 +1,22 @@
-# shotdeck
+# Shotdeck
 
-macOS menu-bar app: hotkey region capture into a review PDF with PASS/FAIL boxes, AirDrop send, annotation-return tracking
+A macOS menu-bar app that captures a remembered screen region, builds a one-screenshot-per-page PDF, AirDrops it to an iPad for markup, then watches for the annotated file to come back.
+
+## Hotkeys
+
+- **⌥⇧1** — pick a new region, then capture it.
+- **⌥⇧2** — capture the remembered region instantly (no picker).
+
+## Screen Recording permission
+
+On first launch macOS asks once for Screen Recording. Grant it at **System Settings > Privacy & Security > Screen Recording**. You never have to do this again as long as the app is not re-signed with a different identity.
+
+The grant is bound to the bundle identifier `ai.flowmaster.shotdeck` plus the code signature. Changing either one forces a fresh prompt.
+
+## Build
+
+```bash
+swift build && swift test
+./scripts/build-app.sh          # signed .app for daily use
+open .build/Shotdeck.app
+```

Sources/Shotdeck/AppModel.swift

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+import AppKit
+import Carbon.HIToolbox
+import Foundation
+import Observation
+import SwiftUI
+import ShotdeckCore
+
+@MainActor
+public protocol SendCapable: AnyObject {
+    func send(anchor: NSView?) async
+}
+
+@MainActor
+public protocol SettingsWindowPresenting: AnyObject {
+    func presentSettingsWindow()
+}
+
+@MainActor
+public protocol ReturnsSectionProviding: AnyObject {
+    @ViewBuilder func returnsSection() -> AnyView
+}
+
+@MainActor
+@Observable
+public final class AppModel {
+    public private(set) var session: CaptureSession
+    public private(set) var region: CaptureRegion?
+    public private(set) var screenRecordingGranted: Bool
+    public private(set) var allReturns: [ReturnedDocument] = []
+    public private(set) var commentedReturns: [ReturnedDocument] = []
+    public private(set) var statusLine: String?
+    public private(set) var isCapturing: Bool = false
+    public private(set) var isSending: Bool = false
+    public private(set) var outboxDisplayName: String
+    public private(set) var watchFolderDisplayName: String
+    /// Live outbox; WP-4b reads this (not `paths.outbox`) so Settings folder changes take effect.
+    public private(set) var outboxURL: URL
+    /// Live watch folder; WP-4c updates this alongside `ReturnWatcher.updateWatchFolder`.
+    public private(set) var watchFolderURL: URL
+
+    let paths: AppSupportPaths
+    let spool: SpoolStore
+    let composer: PDFComposer
+    let capturer: ScreenCapturer
+    let hotkeys: HotkeyCenter
+    let picker: RegionPickerController
+    let ledger: ReturnLedger
+    let watcher: ReturnWatcher
+
+    public init(
+        paths: AppSupportPaths,
+        spool: SpoolStore,
+        composer: PDFComposer,
+        capturer: ScreenCapturer,
+        hotkeys: HotkeyCenter,
+        picker: RegionPickerController,
+        ledger: ReturnLedger,
+        watcher: ReturnWatcher
+    ) {
+        self.paths = paths
+        self.spool = spool
+        self.composer = composer
+        self.capturer = capturer
+        self.hotkeys = hotkeys
+        self.picker = picker
+        self.ledger = ledger
+        self.watcher = watcher
+        self.session = CaptureSession(
+            id: UUID(),
+            createdAt: Date(),
+            state: .open,
+            captures: [],
+            pdfFileName: nil
+        )
+        self.region = nil
+        self.screenRecordingGranted = ScreenCapturer.isScreenRecordingGranted
+        // Seeded from FolderSettings.resolve() via resolvedAppSupportPaths — never .standard().
+        let folders = FolderSettings.resolve()
+        self.outboxURL = folders.outbox
+        self.watchFolderURL = folders.watch
+        self.outboxDisplayName = folders.outbox.lastPathComponent
+        self.watchFolderDisplayName = folders.watch.lastPathComponent
+    }
+
+    // MARK: Seam mutators — the only way a WP-4b/4c extension changes state.
+
+    func setStatus(_ text: String?) { statusLine = text }
+    func setSending(_ value: Bool) { isSending = value }
+    func setCapturing(_ value: Bool) { isCapturing = value }
+    func replaceSession(_ new: CaptureSession) { session = new }
+    func replaceRegion(_ new: CaptureRegion?) { region = new }
+    func setReturns(all: [ReturnedDocument], commented: [ReturnedDocument]) {
+        allReturns = all
+        commentedReturns = commented
+    }
+    func setFolderDisplayNames(outbox: String, watch: String) {
+        outboxDisplayName = outbox
+        watchFolderDisplayName = watch
+    }
+    func setFolderURLs(outbox: URL, watch: URL) {
+        outboxURL = outbox
+        watchFolderURL = watch
+        setFolderDisplayNames(outbox: outbox.lastPathComponent, watch: watch.lastPathComponent)
+    }
+
+    public var iconState: MenuIconState {
+        if !screenRecordingGranted { return .recordingMissing }
+        if isCapturing { return .capturing }
+        if region == nil { return .noRegion }
+        if session.captures.isEmpty { return .regionEmpty }
+        return .hasCaptures(session.captures.count)
+    }
+
+    public func bootstrap() async {
+        if let data = UserDefaults.standard.data(forKey: CaptureRegion.defaultsKey),
+           let decoded = try? JSONDecoder().decode(CaptureRegion.self, from: data),
+           decoded.isStillValid {
+            replaceRegion(decoded)
+        }
+
+        do {
+            let recovered = try await spool.currentSession()
+            replaceSession(recovered)
+        } catch {
+            setStatus((error as? ShotdeckError)?.errorDescription ?? "Could not open the spool.")
+        }
+
+        do {
+            let initial = try await ledger.all()
+            let commented = try await ledger.commented()
+            setReturns(all: initial, commented: commented)
+        } catch {
+            // Empty ledger on first run is not an error.
+        }
+
+        do {
+            try await watcher.start { [weak self] _ in
+                Task { @MainActor in
+                    guard let self else { return }
+                    let all = (try? await self.ledger.all()) ?? []
+                    let commented = (try? await self.ledger.commented()) ?? []
+                    self.setReturns(all: all, commented: commented)
+                }
+            }
+        } catch {
+            setStatus((error as? ShotdeckError)?.errorDescription ?? "Could not watch the return folder.")
+        }
+
+        let registered = hotkeys.register(
+            id: "capture",
+            keyCode: UInt32(kVK_ANSI_2),
+            modifiers: UInt32(optionKey | shiftKey)
+        ) { [weak self] in
+            Task { await self?.captureNow() }
+        }
+        if !registered {
+            setStatus("⌥⇧2 is already used by another app — capture only works from the menu.")
+        }
+    }
+
+    public func captureNow() async {
+        guard !isCapturing else { return }
+        setCapturing(true)
+        defer { setCapturing(false) }
+
+        var target = region
+        if target == nil {
+            target = await withCheckedContinuation { (cont: CheckedContinuation<CaptureRegion?, Never>) in
+                picker.pick { picked in cont.resume(returning: picked) }
+            }
+            guard let picked = target else {
+                setStatus("No region selected.")
+                return
+            }
+            persistRegion(picked)
+        }
+        guard let region = target else { return }
+
+        do {
+            let image = try await capturer.capture(region)
+            let capture = try await spool.append(
+                pngData: image.pngData,
+                pixelWidth: image.pixelWidth,
+                pixelHeight: image.pixelHeight,
+                scale: image.scale,
+                capturedAt: Date()
+            )
+            replaceSession(try await spool.currentSession())
+            setStatus("Captured page \(capture.sequence).")
+        } catch {
+            screenRecordingGranted = ScreenCapturer.isScreenRecordingGranted
+            setStatus((error as? ShotdeckError)?.errorDescription ?? "The screenshot could not be taken.")
+        }
+    }
+
+    public func rePickRegion() async {
+        let picked = await withCheckedContinuation { (cont: CheckedContinuation<CaptureRegion?, Never>) in
+            picker.pick { cont.resume(returning: $0) }
+        }
+        guard let picked else { return }
+        persistRegion(picked)
+        setStatus("Region set: \(Int(picked.rect.width)) × \(Int(picked.rect.height)).")
+    }
+
+    public func removeCapture(id: UUID) async {
+        do {
+            // D-11: SpoolStore.remove MOVES the PNG to <session>/removed/; it is never unlinked.
+            replaceSession(try await spool.remove(captureID: id))
+        } catch {
+            setStatus((error as? ShotdeckError)?.errorDescription ?? "Could not remove that capture.")
+        }
+    }
+
+    public func copyCommentedLinks() async {
+        do {
+            let text = try await ledger.clipboardText()
+            let pasteboard = NSPasteboard.general
+            pasteboard.clearContents()
+            pasteboard.setString(text, forType: .string)
+            let count = commentedReturns.count
+            setStatus("Copied \(count) link\(count == 1 ? "" : "s").")
+        } catch {
+            setStatus((error as? ShotdeckError)?.errorDescription ?? "Nothing to copy.")
+        }
+    }
+
+    public func openSpoolFolder() {
+        NSWorkspace.shared.open(paths.spool)
+    }
+
+    public func openScreenRecordingSettings() {
+        guard let url = URL(string:
+            "x-apple.systempreferences:com.apple.preference.security?Privacy_ScreenCapture") else {
+            setStatus("Could not open System Settings.")
+            return
+        }
+        NSWorkspace.shared.open(url)
+    }
+
+    private func persistRegion(_ picked: CaptureRegion) {
+        replaceRegion(picked)
+        if let encoded = try? JSONEncoder().encode(picked) {
+            UserDefaults.standard.set(encoded, forKey: CaptureRegion.defaultsKey)
+        }
+    }
+}
+
+public enum MenuIconState: Equatable {
+    case noRegion, regionEmpty, hasCaptures(Int), capturing, recordingMissing
+
+    public var symbolName: String {
+        switch self {
+        case .noRegion: return "viewfinder"
+        case .regionEmpty: return "viewfinder.rectangular"
+        case .hasCaptures: return "viewfinder.rectangular"
+        case .capturing: return "viewfinder.circle.fill"
+        case .recordingMissing: return "exclamationmark.triangle"
+        }
+    }
+
+    public var countText: String? {
+        if case .hasCaptures(let n) = self { return "\(n)" }
+        return nil
+    }
+}

Sources/Shotdeck/MenuBarView.swift

@@ -0,0 +1,180 @@
+import AppKit
+import SwiftUI
+import ShotdeckCore
+
+struct MenuBarView: View {
+    @Environment(AppModel.self) private var model
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 8) {
+            statusRow
+            SessionStrip()
+            Divider()
+            actionsList
+            if !model.allReturns.isEmpty {
+                Divider()
+                returnsBlock
+            }
+        }
+        .padding(10)
+        .frame(width: 320, alignment: .leading)
+        .controlSize(.small)
+    }
+
+    @ViewBuilder
+    private var statusRow: some View {
+        if !model.screenRecordingGranted {
+            HStack(alignment: .top, spacing: 6) {
+                Image(systemName: "exclamationmark.triangle")
+                    .foregroundStyle(.yellow)
+                VStack(alignment: .leading, spacing: 4) {
+                    Text(
+                        ShotdeckError.screenRecordingNotGranted.errorDescription
+                            ?? "Screen Recording is turned off."
+                    )
+                    .font(.caption)
+                    .fixedSize(horizontal: false, vertical: true)
+                    Button("Open Screen Recording settings") {
+                        model.openScreenRecordingSettings()
+                    }
+                }
+            }
+        } else {
+            Text(model.statusLine ?? defaultStatusText)
+                .font(.caption)
+                .foregroundStyle(.primary)
+                .fixedSize(horizontal: false, vertical: true)
+        }
+    }
+
+    private var defaultStatusText: String {
+        guard let region = model.region else {
+            return "No region yet — press ⌥⇧2 to pick one."
+        }
+        let w = Int(region.rect.width)
+        let h = Int(region.rect.height)
+        let display = displayName(for: region)
+        if model.session.isEmpty {
+            return "Region \(w) × \(h) on \(display) · Nothing captured yet."
+        }
+        let count = model.session.captures.count
+        return "\(count) captures · region \(w) × \(h) on \(display)"
+    }
+
+    private func displayName(for region: CaptureRegion) -> String {
+        for (index, screen) in NSScreen.screens.enumerated() {
+            let id = (screen.deviceDescription[NSDeviceDescriptionKey("NSScreenNumber")] as? NSNumber)?
+                .uint32Value
+            if id == region.displayID {
+                return "Display \(index + 1)"
+            }
+        }
+        return "Display 1"
+    }
+
+    private var actionsList: some View {
+        VStack(alignment: .leading, spacing: 2) {
+            Button {
+                let anchor = NSApp.keyWindow?.contentView
+                if let sender = model as? SendCapable {
+                    Task { await sender.send(anchor: anchor) }
+                } else {
+                    model.setStatus("Send is not available in this build.")
+                }
+            } label: {
+                actionLabel("Send…")
+            }
+            .disabled(model.session.isEmpty || model.isSending)
+
+            Button {
+                Task { await model.captureNow() }
+            } label: {
+                actionLabel("Capture now", trailing: "⌥⇧2")
+            }
+            .disabled(model.isCapturing)
+
+            Button {
+                Task { await model.rePickRegion() }
+            } label: {
+                actionLabel("Re-select area")
+            }
+
+            Button {
+                Task { await model.copyCommentedLinks() }
+            } label: {
+                actionLabel(
+                    "Copy commented links",
+                    trailing: model.commentedReturns.isEmpty ? nil : "\(model.commentedReturns.count)"
+                )
+            }
+            .disabled(model.commentedReturns.isEmpty)
+
+            Button {
+                model.openSpoolFolder()
+            } label: {
+                actionLabel("Open spool folder")
+            }
+
+            Button {
+                if let presenter = model as? SettingsWindowPresenting {
+                    presenter.presentSettingsWindow()
+                } else {
+                    model.setStatus("Settings is not available in this build.")
+                }
+            } label: {
+                actionLabel("Settings…")
+            }
+
+            Button {
+                NSApp.terminate(nil)
+            } label: {
+                actionLabel("Quit Shotdeck")
+            }
+        }
+        .buttonStyle(.plain)
+    }
+
+    private func actionLabel(_ title: String, trailing: String? = nil) -> some View {
+        HStack(spacing: 8) {
+            Text(title)
+            Spacer(minLength: 8)
+            if let trailing {
+                Text(trailing)
+                    .foregroundStyle(.secondary)
+                    .monospacedDigit()
+            }
+        }
+        .frame(maxWidth: .infinity, alignment: .leading)
+        .contentShape(Rectangle())
+        .padding(.vertical, 3)
+    }
+
+    @ViewBuilder
+    private var returnsBlock: some View {
+        if let provider = model as? ReturnsSectionProviding {
+            provider.returnsSection()
+        } else {
+            VStack(alignment: .leading, spacing: 4) {
+                Text("Came back from your device")
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+                ForEach(newestReturns.prefix(8)) { doc in
+                    HStack(spacing: 8) {
+                        Text(doc.fileURL.lastPathComponent)
+                            .lineLimit(1)
+                        Spacer(minLength: 8)
+                        Text(doc.isCommented
+                             ? "\(doc.annotatedPages.count) page\(doc.annotatedPages.count == 1 ? "" : "s") marked"
+                             : "not marked")
+                            .font(.caption)
+                            .foregroundStyle(doc.isCommented ? .primary : .secondary)
+                    }
+                }
+            }
+        }
+    }
+
+    private var newestReturns: [ReturnedDocument] {
+        model.allReturns.sorted { $0.detectedAt > $1.detectedAt }
+    }
+}

Sources/Shotdeck/RegionPickerController.swift

@@ -0,0 +1,181 @@
+import AppKit
+import ShotdeckCore
+
+@MainActor
+public final class RegionPickerController {
+    private var windows: [RegionPickerWindow] = []
+    private var monitor: Any?
+    private var completion: (@MainActor (CaptureRegion?) -> Void)?
+    private var dragStart: NSPoint?
+    private var startScreen: NSScreen?
+    private var cursorPushed = false
+
+    public init() {}
+
+    /// Presents one overlay per attached screen. A pick already in progress is cancelled
+    /// (its completion called with nil) before the new one starts — never leaves a caller
+    /// waiting forever on a dropped re-entrant call.
+    public func pick(completion: @escaping @MainActor (CaptureRegion?) -> Void) {
+        if self.completion != nil {
+            finish(region: nil)
+        }
+        self.completion = completion
+        presentOverlays()
+    }
+
+    private func presentOverlays() {
+        let screens = NSScreen.screens
+        guard !screens.isEmpty else {
+            finish(region: nil)
+            return
+        }
+
+        NSCursor.crosshair.push()
+        cursorPushed = true
+
+        windows = screens.map { RegionPickerWindow(screen: $0) }
+        for window in windows {
+            window.orderFrontRegardless()
+        }
+        // Nonactivating panel can become key without activating the app; needed so
+        // Escape reaches the local monitor immediately, before any mouse click.
+        let mouse = NSEvent.mouseLocation
+        let keyWindow = windows.first(where: { $0.coveringScreen.frame.contains(mouse) })
+            ?? windows[0]
+        keyWindow.makeKey()
+
+        monitor = NSEvent.addLocalMonitorForEvents(
+            matching: [.leftMouseDown, .leftMouseDragged, .leftMouseUp, .keyDown]
+        ) { [weak self] event in
+            guard let self else { return event }
+            // NSEvent is not Sendable; lift the two Sendable fields the handler
+            // needs. Mouse geometry is read from NSEvent.mouseLocation on the
+            // main thread inside the isolated methods, per spec.
+            let type = event.type
+            let keyCode = event.keyCode
+            let consume = MainActor.assumeIsolated {
+                self.handle(type: type, keyCode: keyCode)
+            }
+            return consume ? nil : event
+        }
+    }
+
+    /// Returns `true` when the event should be swallowed.
+    private func handle(type: NSEvent.EventType, keyCode: UInt16) -> Bool {
+        switch type {
+        case .keyDown:
+            if keyCode == 53 { // kVK_Escape
+                finish(region: nil)
+                return true
+            }
+            return false
+        case .leftMouseDown:
+            handleMouseDown()
+            return false
+        case .leftMouseDragged:
+            handleMouseDragged()
+            return false
+        case .leftMouseUp:
+            handleMouseUp()
+            return false
+        default:
+            return false
+        }
+    }
+
+    private func handleMouseDown() {
+        let point = NSEvent.mouseLocation
+        dragStart = point
+        startScreen = NSScreen.screens.first(where: { $0.frame.contains(point) })
+            ?? NSScreen.screens.first
+        guard let startScreen else { return }
+        let local = Self.localRect(
+            from: CGRect(origin: point, size: .zero).intersection(startScreen.frame),
+            on: startScreen
+        )
+        window(for: startScreen)?.updateSelection(localRect: local, sizeText: "0 x 0")
+        for window in windows where window.coveringScreen !== startScreen {
+            window.updateSelection(localRect: nil, sizeText: nil)
+        }
+    }
+
+    private func handleMouseDragged() {
+        guard dragStart != nil, startScreen != nil else { return }
+        applyLiveSelection()
+    }
+
+    private func handleMouseUp() {
+        guard let startScreen else {
+            dragStart = nil
+            return
+        }
+        guard let rect = currentClampedRect(), rect.width >= 8, rect.height >= 8 else {
+            // Mis-click: reset drag state, leave every window open and fully dimmed.
+            dragStart = nil
+            self.startScreen = nil
+            for window in windows {
+                window.updateSelection(localRect: nil, sizeText: nil)
+            }
+            return
+        }
+        let region = CaptureRegion.fromAppKit(rect: rect, on: startScreen)
+        finish(region: region)
+    }
+
+    private func applyLiveSelection() {
+        guard let startScreen, let rect = currentClampedRect() else { return }
+        let local = Self.localRect(from: rect, on: startScreen)
+        let text = "\(Int(rect.width)) x \(Int(rect.height))"
+        window(for: startScreen)?.updateSelection(localRect: local, sizeText: text)
+        for window in windows where window.coveringScreen !== startScreen {
+            window.updateSelection(localRect: nil, sizeText: nil)
+        }
+    }
+
+    /// Normalize the drag (so bottom-right → up-left is not misjudged) then clamp
+    /// to the screen the gesture started on — never selects across displays.
+    private func currentClampedRect() -> CGRect? {
+        guard let dragStart, let startScreen else { return nil }
+        let current = NSEvent.mouseLocation
+        let normalized = CGRect(
+            x: min(dragStart.x, current.x),
+            y: min(dragStart.y, current.y),
+            width: abs(current.x - dragStart.x),
+            height: abs(current.y - dragStart.y)
+        )
+        return normalized.intersection(startScreen.frame)
+    }
+
+    private func window(for screen: NSScreen) -> RegionPickerWindow? {
+        windows.first { $0.coveringScreen === screen }
+    }
+
+    private static func localRect(from rect: CGRect, on screen: NSScreen) -> CGRect {
+        CGRect(
+            x: rect.minX - screen.frame.minX,
+            y: rect.minY - screen.frame.minY,
+            width: rect.width,
+            height: rect.height
+        )
+    }
+
+    private func finish(region: CaptureRegion?) {
+        if let monitor {
+            NSEvent.removeMonitor(monitor)
+            self.monitor = nil
+        }
+        if cursorPushed {
+            NSCursor.pop()
+            cursorPushed = false
+        }
+        for window in windows {
+            window.orderOut(nil)
+        }
+        windows.removeAll()
+        dragStart = nil
+        startScreen = nil
+        let done = completion
+        completion = nil
+        done?(region)
+    }
+}

Sources/Shotdeck/RegionPickerWindow.swift

@@ -0,0 +1,110 @@
+import AppKit
+
+/// Full-screen dim overlay for one attached display. Subclasses `NSPanel` with
+/// `.nonactivatingPanel` so it can accept mouse and key events without activating
+/// Shotdeck or stealing the frontmost app beyond those events.
+@MainActor
+final class RegionPickerWindow: NSPanel {
+    let coveringScreen: NSScreen
+    private let pickerView: RegionPickerView
+
+    init(screen: NSScreen) {
+        self.coveringScreen = screen
+        self.pickerView = RegionPickerView(frame: CGRect(origin: .zero, size: screen.frame.size))
+        super.init(
+            contentRect: screen.frame,
+            styleMask: [.borderless, .nonactivatingPanel],
+            backing: .buffered,
+            defer: false
+        )
+        setFrame(screen.frame, display: false)
+        level = .screenSaver
+        isOpaque = false
+        backgroundColor = .clear
+        ignoresMouseEvents = false
+        hasShadow = false
+        isMovable = false
+        hidesOnDeactivate = false
+        isFloatingPanel = true
+        becomesKeyOnlyIfNeeded = false
+        animationBehavior = .none
+        collectionBehavior = [.canJoinAllSpaces, .fullScreenAuxiliary, .stationary]
+        contentView = pickerView
+    }
+
+    override var canBecomeKey: Bool { true }
+    override var canBecomeMain: Bool { false }
+
+    /// `localRect` is in this window's coordinates (screen.frame origin subtracted).
+    /// Pass `nil` to restore the full dim with no punch and no size chip.
+    func updateSelection(localRect: CGRect?, sizeText: String?) {
+        pickerView.selectionLocalRect = localRect
+        pickerView.sizeChipText = sizeText
+        pickerView.needsDisplay = true
+    }
+}
+
+/// Draws ~35% black over the screen with an even-odd punch for the live selection,
+/// a thin light border, and the size-readout chip.
+@MainActor
+private final class RegionPickerView: NSView {
+    var selectionLocalRect: CGRect?
+    var sizeChipText: String?
+
+    override var isOpaque: Bool { false }
+    override var acceptsFirstResponder: Bool { true }
+
+    override func draw(_ dirtyRect: NSRect) {
+        super.draw(dirtyRect)
+
+        let dim = NSColor.black.withAlphaComponent(0.35)
+        let path = NSBezierPath(rect: bounds)
+        if let sel = selectionLocalRect, sel.width > 0, sel.height > 0 {
+            path.append(NSBezierPath(rect: sel))
+            path.windingRule = .evenOdd
+        }
+        dim.setFill()
+        path.fill()
+
+        guard let sel = selectionLocalRect, sel.width > 0, sel.height > 0 else { return }
+
+        NSColor.white.withAlphaComponent(0.85).setStroke()
+        let border = NSBezierPath(rect: sel)
+        border.lineWidth = 1
+        border.stroke()
+
+        if let text = sizeChipText {
+            drawSizeChip(text, above: sel)
+        }
+    }
+
+    private func drawSizeChip(_ text: String, above sel: CGRect) {
+        let attrs: [NSAttributedString.Key: Any] = [
+            .font: NSFont.systemFont(ofSize: NSFont.smallSystemFontSize),
+            .foregroundColor: NSColor.white,
+        ]
+        let nsText = text as NSString
+        let textSize = nsText.size(withAttributes: attrs)
+        let padX: CGFloat = 8
+        let padY: CGFloat = 4
+        let chipSize = CGSize(
+            width: ceil(textSize.width) + padX * 2,
+            height: ceil(textSize.height) + padY * 2
+        )
+
+        var origin = CGPoint(x: sel.minX, y: sel.maxY + 6)
+        if origin.y + chipSize.height > bounds.maxY {
+            origin.y = sel.minY - 6 - chipSize.height
+        }
+        origin.x = min(max(origin.x, bounds.minX + 4), bounds.maxX - chipSize.width - 4)
+        origin.y = min(max(origin.y, bounds.minY + 4), bounds.maxY - chipSize.height - 4)
+
+        let chipRect = CGRect(origin: origin, size: chipSize)
+        NSColor.black.withAlphaComponent(0.75).setFill()
+        NSBezierPath(roundedRect: chipRect, xRadius: 4, yRadius: 4).fill()
+        nsText.draw(
+            at: CGPoint(x: chipRect.minX + padX, y: chipRect.minY + padY),
+            withAttributes: attrs
+        )
+    }
+}

Sources/Shotdeck/SessionStrip.swift

@@ -0,0 +1,78 @@
+import AppKit
+import SwiftUI
+import ShotdeckCore
+
+struct SessionStrip: View {
+    @Environment(AppModel.self) private var model
+
+    var body: some View {
+        if model.session.captures.isEmpty {
+            Text("Nothing captured yet.")
+                .font(.caption)
+                .foregroundStyle(.secondary)
+                .frame(maxWidth: .infinity, minHeight: 64, alignment: .leading)
+        } else {
+            ScrollView(.horizontal, showsIndicators: false) {
+                HStack(alignment: .top, spacing: 6) {
+                    ForEach(model.session.captures) { capture in
+                        SessionThumb(capture: capture)
+                    }
+                }
+            }
+            .frame(height: 64)
+        }
+    }
+}
+
+private struct SessionThumb: View {
+    @Environment(AppModel.self) private var model
+    let capture: Capture
+    @State private var hovering = false
+
+    var body: some View {
+        ZStack(alignment: .topLeading) {
+            thumbnail
+            Text("\(capture.sequence)")
+                .font(.system(size: 9, weight: .bold))
+                .foregroundStyle(.white)
+                .padding(.horizontal, 4)
+                .padding(.vertical, 1)
+                .background(.black.opacity(0.65))
+                .clipShape(RoundedRectangle(cornerRadius: 2, style: .continuous))
+                .padding(3)
+            if hovering {
+                VStack {
+                    Spacer()
+                    Button("Remove") {
+                        Task { await model.removeCapture(id: capture.id) }
+                    }
+                    .font(.system(size: 10, weight: .semibold))
+                    .buttonStyle(.plain)
+                    .foregroundStyle(.white)
+                    .frame(maxWidth: .infinity)
+                    .padding(.vertical, 3)
+                    .background(.black.opacity(0.7))
+                }
+            }
+        }
+        .frame(height: 64)
+        .clipped()
+        .onHover { hovering = $0 }
+        .help(DubaiTime.stamp(capture.capturedAt))
+    }
+
+    @ViewBuilder
+    private var thumbnail: some View {
+        let url = model.paths.sessionDirectory(model.session.id).appendingPathComponent(capture.fileName)
+        if let image = NSImage(contentsOf: url) {
+            Image(nsImage: image)
+                .resizable()
+                .aspectRatio(contentMode: .fit)
+                .frame(height: 64)
+        } else {
+            Rectangle()
+                .fill(Color.secondary.opacity(0.2))
+                .frame(width: 64, height: 64)
+        }
+    }
+}

Sources/Shotdeck/main.swift

@@ -0,0 +1,75 @@
+import AppKit
+import SwiftUI
+import ShotdeckCore
+
+// SwiftPM treats a file named main.swift as top-level code, which forbids `@main`.
+// App.main() is the equivalent entry point.
+ShotdeckApp.main()
+
+struct ShotdeckApp: App {
+    @NSApplicationDelegateAdaptor(AppDelegate.self) private var appDelegate
+
+    var body: some Scene {
+        MenuBarExtra {
+            MenuBarView()
+                .environment(appDelegate.model)
+        } label: {
+            let state = appDelegate.model.iconState
+            HStack(spacing: 4) {
+                Image(systemName: state.symbolName)
+                if let count = state.countText {
+                    Text(count).font(.system(size: 11, weight: .semibold))
+                }
+            }
+            .accessibilityLabel("Shotdeck")
+        }
+        .menuBarExtraStyle(.window)
+    }
+}
+
+@MainActor
+final class AppDelegate: NSObject, NSApplicationDelegate {
+    let model: AppModel
+
+    override init() {
+        NSApplication.shared.setActivationPolicy(.accessory)
+        model = AppDelegate.makeLaunchModel()
+        super.init()
+    }
+
+    func applicationDidFinishLaunching(_ notification: Notification) {
+        Task { await model.bootstrap() }
+    }
+
+    private static func makeLaunchModel() -> AppModel {
+        do {
+            let paths = try FolderSettings.resolvedAppSupportPaths()
+            return try makeModel(paths: paths)
+        } catch {
+            Log.ui.critical(
+                "AppModel init failed: \(String(describing: error), privacy: .public)"
+            )
+            let tmp = FileManager.default.temporaryDirectory
+            let fallbackRoot = tmp.appendingPathComponent("Shotdeck-fallback", isDirectory: true)
+            // Safe: temp-dir creation for a path this process controls cannot legitimately fail.
+            let fallback = try! AppSupportPaths(root: fallbackRoot, outbox: tmp, watchFolder: tmp)
+            let model = try! makeModel(paths: fallback)
+            model.setStatus("Shotdeck could not access its storage folder. Captures will not persist.")
+            return model
+        }
+    }
+
+    private static func makeModel(paths: AppSupportPaths) throws -> AppModel {
+        let ledger = try ReturnLedger(paths: paths)
+        return AppModel(
+            paths: paths,
+            spool: try SpoolStore(paths: paths),
+            composer: PDFComposer(),
+            capturer: ScreenCapturer(),
+            hotkeys: HotkeyCenter(),
+            picker: RegionPickerController(),
+            ledger: ledger,
+            watcher: ReturnWatcher(paths: paths, ledger: ledger)
+        )
+    }
+}

Sources/ShotdeckCore/Capture/CaptureRegion.swift

@@ -0,0 +1,58 @@
+import Foundation
+import AppKit  // NSScreen, NSDeviceDescriptionKey — macOS-only target, no portability concern
+
+/// A remembered rectangle, in CoreGraphics global display coordinates (origin top-left,
+/// y increasing downward — see the conversion note below).
+public struct CaptureRegion: Codable, Sendable, Equatable {
+    public let displayID: CGDirectDisplayID
+    public let rect: CGRect
+    public let capturedScale: CGFloat
+
+    public init(displayID: CGDirectDisplayID, rect: CGRect, capturedScale: CGFloat) {
+        self.displayID = displayID
+        self.rect = rect
+        self.capturedScale = capturedScale
+    }
+
+    /// Converts an AppKit rect in GLOBAL AppKit coordinates (bottom-left origin, y increasing
+    /// upward, anchored at the bottom-left of the PRIMARY screen — exactly what
+    /// `NSWindow.frame`, `NSEvent.mouseLocation` and `NSScreen.frame` already report; no
+    /// screen-local conversion is needed here) into global CoreGraphics coordinates
+    /// (top-left origin, y increasing downward, same primary-screen anchor). Both coordinate
+    /// systems share the SAME horizontal origin and the SAME anchor rectangle (the primary
+    /// screen's bounds) — only the vertical axis is mirrored around the primary's height.
+    /// That is why the flip below is correct for every attached screen, including one with a
+    /// negative AppKit x (to the left of primary) or a y that places it above the primary
+    /// (whose CG y then comes out negative): x is untouched, and the primary height is the
+    /// one fixed reference both systems agree on regardless of which physical screen the
+    /// rect is actually on.
+    public static func fromAppKit(rect: CGRect, on screen: NSScreen) -> CaptureRegion {
+        let displayID = (screen.deviceDescription[NSDeviceDescriptionKey("NSScreenNumber")]
+            as? NSNumber)?.uint32Value ?? CGMainDisplayID()
+        let primaryHeight = NSScreen.screens.first?.frame.height ?? screen.frame.height
+        return fromAppKit(rect: rect, displayID: displayID,
+                           capturedScale: screen.backingScaleFactor, primaryHeight: primaryHeight)
+    }
+
+    /// Injectable overload for deterministic geometry tests — no dependency on real attached
+    /// displays. The public overload above is a thin adapter over this.
+    static func fromAppKit(rect: CGRect, displayID: CGDirectDisplayID,
+                            capturedScale: CGFloat, primaryHeight: CGFloat) -> CaptureRegion {
+        let cgY = primaryHeight - rect.origin.y - rect.height
+        let cgRect = CGRect(x: rect.origin.x, y: cgY, width: rect.width, height: rect.height)
+        return CaptureRegion(displayID: displayID, rect: cgRect, capturedScale: capturedScale)
+    }
+
+    /// True when `displayID` is still attached AND `rect` still lies inside its current
+    /// bounds. Uses `CGDisplayIsActive` (returns 0 safely for an unknown id, never traps) and
+    /// `CGDisplayBounds` — both real CoreGraphics calls, no injection needed since this is a
+    /// live-state check by design.
+    public var isStillValid: Bool {
+        guard CGDisplayIsActive(displayID) != 0 else { return false }
+        let bounds = CGDisplayBounds(displayID)
+        return bounds.contains(rect)
+    }
+
+    /// Persisted in UserDefaults under this key BY THE APP (WP-4a), never by this type.
+    public static let defaultsKey = "ai.flowmaster.shotdeck.region"
+}

Sources/ShotdeckCore/Capture/HotkeyCenter.swift

@@ -0,0 +1,115 @@
+import Carbon.HIToolbox
+import Foundation
+
+/// Carbon's C event handler cannot capture Swift closures, so live handlers are kept in one
+/// process-wide table keyed by the numeric EventHotKeyID Carbon hands back on fire. Safe
+/// because InstallEventHandler on GetApplicationEventTarget() always delivers on the main
+/// thread, and every access here happens either from a @MainActor HotkeyCenter method or from
+/// the C callback below, which this process only ever invokes on the main run loop.
+private final class HotkeyDispatchTable: @unchecked Sendable {
+    static let shared = HotkeyDispatchTable()
+    private var handlers: [UInt32: @MainActor () -> Void] = [:]
+    private init() {}
+    func set(_ numericID: UInt32, _ handler: @escaping @MainActor () -> Void) {
+        handlers[numericID] = handler
+    }
+    func remove(_ numericID: UInt32) { handlers.removeValue(forKey: numericID) }
+    func fire(_ numericID: UInt32) { MainActor.assumeIsolated { handlers[numericID]?() } }
+}
+
+private func shotdeckCarbonHotkeyHandler(
+    _ nextHandler: EventHandlerCallRef?, _ event: EventRef?, _ userData: UnsafeMutableRawPointer?
+) -> OSStatus {
+    guard let event else { return OSStatus(eventNotHandledErr) }
+    var hotKeyID = EventHotKeyID()
+    let status = GetEventParameter(event, EventParamName(kEventParamDirectObject),
+        EventParamType(typeEventHotKeyID), nil, MemoryLayout<EventHotKeyID>.size, nil, &hotKeyID)
+    guard status == noErr else { return status }
+    HotkeyDispatchTable.shared.fire(hotKeyID.id)
+    return noErr
+}
+
+/// Four-character creator code used for every `EventHotKeyID` this process registers.
+private let shotdeckHotKeySignature: OSType = 0x53484F54 // "SHOT"
+
+@MainActor
+public final class HotkeyCenter {
+    private var bindings: [String: (ref: EventHotKeyRef, numericID: UInt32)] = [:]
+    private var nextNumericID: UInt32 = 1
+
+    private static var didInstallGlobalCarbonHandler = false
+    private static var carbonHandlerRef: EventHandlerRef?
+
+    public init() { HotkeyCenter.installGlobalCarbonHandlerIfNeeded() }
+
+    /// Registers a hotkey. `id` is a caller-chosen stable identifier. Re-registering the same
+    /// `id` first unregisters its previous binding, then attempts the new one (idempotent).
+    /// Returns false when Carbon's `RegisterEventHotKey` reports a non-`noErr` status — the
+    /// most common cause is the same keyCode+modifiers combination already being claimed
+    /// system-wide by this or another process.
+    @discardableResult
+    public func register(
+        id: String,
+        keyCode: UInt32,
+        modifiers: UInt32,
+        handler: @escaping @MainActor () -> Void
+    ) -> Bool {
+        unregister(id: id)
+
+        let hotKeyID = EventHotKeyID(signature: shotdeckHotKeySignature, id: nextNumericID)
+        var ref: EventHotKeyRef?
+        let status = RegisterEventHotKey(
+            keyCode,
+            modifiers,
+            hotKeyID,
+            GetApplicationEventTarget(),
+            0,
+            &ref
+        )
+        guard status == noErr, let ref else {
+            return false
+        }
+        bindings[id] = (ref: ref, numericID: nextNumericID)
+        HotkeyDispatchTable.shared.set(nextNumericID, handler)
+        nextNumericID += 1
+        return true
+    }
+
+    public func unregister(id: String) {
+        guard let binding = bindings.removeValue(forKey: id) else { return }
+        _ = UnregisterEventHotKey(binding.ref)
+        HotkeyDispatchTable.shared.remove(binding.numericID)
+    }
+
+    public func unregisterAll() {
+        let ids = Array(bindings.keys)
+        for id in ids {
+            unregister(id: id)
+        }
+    }
+
+    /// Installs the process-wide Carbon hot-key pressed handler exactly once.
+    private static func installGlobalCarbonHandlerIfNeeded() {
+        guard !didInstallGlobalCarbonHandler else { return }
+        didInstallGlobalCarbonHandler = true
+
+        var handlerRef: EventHandlerRef?
+        var eventTypes = [
+            EventTypeSpec(
+                eventClass: OSType(kEventClassKeyboard),
+                eventKind: OSType(kEventHotKeyPressed)
+            )
+        ]
+        let status = InstallEventHandler(
+            GetApplicationEventTarget(),
+            shotdeckCarbonHotkeyHandler,
+            1,
+            &eventTypes,
+            nil,
+            &handlerRef
+        )
+        if status == noErr {
+            carbonHandlerRef = handlerRef
+        }
+    }
+}

Sources/ShotdeckCore/Capture/ScreenCapturer.swift

@@ -0,0 +1,118 @@
+import ScreenCaptureKit
+import CoreGraphics
+import ImageIO
+import UniformTypeIdentifiers
+import AppKit  // NSScreen only, to read backingScaleFactor as a fallback
+import Foundation
+
+public struct CapturedImage: Sendable {
+    public let pngData: Data
+    public let pixelWidth: Int
+    public let pixelHeight: Int
+    public let scale: CGFloat
+}
+
+public struct ScreenCapturer: Sendable {
+    public init() {}
+
+    /// Does NOT prompt. Reports the current Screen Recording grant.
+    public static var isScreenRecordingGranted: Bool { CGPreflightScreenCaptureAccess() }
+
+    /// Captures `region` at the display's true backing scale. Throws
+    /// `.screenRecordingNotGranted` when the grant is absent — never requests it.
+    public func capture(_ region: CaptureRegion) async throws -> CapturedImage {
+        guard Self.isScreenRecordingGranted else {
+            throw ShotdeckError.screenRecordingNotGranted
+        }
+
+        let content: SCShareableContent
+        do {
+            content = try await SCShareableContent.excludingDesktopWindows(
+                false,
+                onScreenWindowsOnly: true
+            )
+        } catch {
+            throw ShotdeckError.captureFailed(underlying: error.localizedDescription)
+        }
+
+        guard let display = content.displays.first(where: { $0.displayID == region.displayID }) else {
+            throw ShotdeckError.displayNoLongerConnected(displayID: region.displayID)
+        }
+
+        // Bounds/clamp: a resolution change often shrinks the display bounds by a few
+        // points without the region Ben picked being meaningfully wrong; 80% keeps a real
+        // recapture usable while a smaller overlap (e.g. a genuinely different display
+        // swapped in) still throws.
+        let rect: CGRect
+        if display.frame.contains(region.rect) {
+            rect = region.rect
+        } else {
+            let overlap = display.frame.intersection(region.rect)
+            let originalArea = region.rect.width * region.rect.height
+            let overlapArea = overlap.width * overlap.height
+            if originalArea > 0 && overlapArea / originalArea >= 0.8 {
+                rect = overlap
+            } else {
+                throw ShotdeckError.displayNoLongerConnected(displayID: region.displayID)
+            }
+        }
+
+        let localRect = CGRect(
+            x: rect.minX - display.frame.minX,
+            y: rect.minY - display.frame.minY,
+            width: rect.width,
+            height: rect.height
+        )
+
+        guard let mode = CGDisplayCopyDisplayMode(region.displayID) else {
+            throw ShotdeckError.captureFailed(
+                underlying: "no display mode for displayID \(region.displayID)"
+            )
+        }
+        guard mode.width > 0 else {
+            throw ShotdeckError.captureFailed(
+                underlying: "display mode width is 0 for displayID \(region.displayID)"
+            )
+        }
+        let scale = CGFloat(mode.pixelWidth) / CGFloat(mode.width)
+
+        let filter = SCContentFilter(display: display, excludingWindows: [])
+        let configuration = SCStreamConfiguration()
+        configuration.sourceRect = localRect
+        configuration.width = Int((localRect.width * scale).rounded())
+        configuration.height = Int((localRect.height * scale).rounded())
+        configuration.scalesToFit = false
+        configuration.showsCursor = false
+
+        let cgImage: CGImage
+        do {
+            cgImage = try await SCScreenshotManager.captureImage(
+                contentFilter: filter,
+                configuration: configuration
+            )
+        } catch {
+            throw ShotdeckError.captureFailed(underlying: error.localizedDescription)
+        }
+
+        let data = NSMutableData()
+        guard let dest = CGImageDestinationCreateWithData(
+            data,
+            UTType.png.identifier as CFString,
+            1,
+            nil
+        ) else {
+            throw ShotdeckError.captureFailed(underlying: "could not create PNG image destination")
+        }
+        CGImageDestinationAddImage(dest, cgImage, nil)
+        guard CGImageDestinationFinalize(dest) else {
+            throw ShotdeckError.captureFailed(underlying: "PNG encoding failed to finalize")
+        }
+
+        return CapturedImage(
+            pngData: data as Data,
+            pixelWidth: cgImage.width,
+            pixelHeight: cgImage.height,
+            scale: scale
+        )
+    }
+}

Sources/ShotdeckCore/Model/Capture.swift

@@ -0,0 +1,43 @@
+import Foundation
+
+/// One screenshot plus everything needed to place it on a PDF page.
+public struct Capture: Codable, Sendable, Identifiable, Equatable {
+    public let id: UUID
+    /// 1-based position within its session. Stable; never renumbered on delete.
+    public let sequence: Int
+    /// File name only (e.g. "001-A1B2C3D4.png"), never a path.
+    /// The directory is always the owning session's directory.
+    public let fileName: String
+    /// Pixel dimensions of the PNG on disk.
+    public let pixelWidth: Int
+    public let pixelHeight: Int
+    /// Backing scale the capture was taken at (2.0 on Retina). Needed so the PDF
+    /// composer lays the image out at its true point size, not its pixel size.
+    public let scale: CGFloat
+    /// When the screenshot was taken. Always stored as an absolute instant;
+    /// rendered in Asia/Dubai wherever a human sees it.
+    public let capturedAt: Date
+
+    public init(
+        id: UUID,
+        sequence: Int,
+        fileName: String,
+        pixelWidth: Int,
+        pixelHeight: Int,
+        scale: CGFloat,
+        capturedAt: Date
+    ) {
+        self.id = id
+        self.sequence = sequence
+        self.fileName = fileName
+        self.pixelWidth = pixelWidth
+        self.pixelHeight = pixelHeight
+        self.scale = scale
+        self.capturedAt = capturedAt
+    }
+
+    /// True when the image is wider than it is tall. Drives page orientation.
+    public var isLandscape: Bool {
+        pixelWidth > pixelHeight
+    }
+}

Sources/ShotdeckCore/Model/CaptureSession.swift

@@ -0,0 +1,73 @@
+import Foundation
+
+public enum SessionState: String, Codable, Sendable {
+    case open      // accepting captures
+    case archived  // its PDF has been built and sent; kept forever, never deleted
+}
+
+/// The manifest persisted as session.json alongside the PNGs.
+public struct CaptureSession: Codable, Sendable, Identifiable, Equatable {
+    public let id: UUID
+    public let createdAt: Date
+    public private(set) var state: SessionState
+    public private(set) var captures: [Capture]
+    /// Set when the PDF is built, so a re-send reuses the same file.
+    public private(set) var pdfFileName: String?
+
+    public init(
+        id: UUID,
+        createdAt: Date,
+        state: SessionState,
+        captures: [Capture],
+        pdfFileName: String?
+    ) {
+        self.id = id
+        self.createdAt = createdAt
+        self.state = state
+        self.captures = captures
+        self.pdfFileName = pdfFileName
+    }
+
+    public var isEmpty: Bool {
+        captures.isEmpty
+    }
+
+    /// max(sequence)+1, or 1 when empty.
+    public var nextSequence: Int {
+        (captures.map(\.sequence).max() ?? 0) + 1
+    }
+
+    /// Value-semantic: returns a new session; does not mutate `self`.
+    public func appending(_ capture: Capture) -> CaptureSession {
+        CaptureSession(
+            id: id,
+            createdAt: createdAt,
+            state: state,
+            captures: captures + [capture],
+            pdfFileName: pdfFileName
+        )
+    }
+
+    /// Value-semantic: returns a new session; does not mutate `self`.
+    /// Sequence numbers of remaining captures are left unchanged.
+    public func removing(captureID: UUID) -> CaptureSession {
+        CaptureSession(
+            id: id,
+            createdAt: createdAt,
+            state: state,
+            captures: captures.filter { $0.id != captureID },
+            pdfFileName: pdfFileName
+        )
+    }
+
+    /// Value-semantic: returns a new session; does not mutate `self`.
+    public func markArchived(pdfFileName: String) -> CaptureSession {
+        CaptureSession(
+            id: id,
+            createdAt: createdAt,
+            state: .archived,
+            captures: captures,
+            pdfFileName: pdfFileName
+        )
+    }
+}

Sources/ShotdeckCore/Model/ShotdeckError.swift

@@ -0,0 +1,36 @@
+import Foundation
+
+public enum ShotdeckError: Error, LocalizedError, Sendable {
+    case screenRecordingNotGranted
+    case noRegionRemembered
+    case displayNoLongerConnected(displayID: UInt32)
+    case captureFailed(underlying: String)
+    case spoolWriteFailed(path: String, underlying: String)
+    case manifestCorrupt(path: String)
+    case pdfCompositionFailed(reason: String)
+    case airDropUnavailable
+    case noCommentedReturns
+
+    public var errorDescription: String? {
+        switch self {
+        case .screenRecordingNotGranted:
+            return "Screen Recording is turned off. Grant it in System Settings to capture."
+        case .noRegionRemembered:
+            return "No capture region is set. Choose 'Re-select area' from the Shotdeck menu."
+        case .displayNoLongerConnected:
+            return "The display used for capture is no longer connected."
+        case .captureFailed(let underlying):
+            return "The screenshot could not be taken. \(underlying)"
+        case .spoolWriteFailed(_, let underlying):
+            return "The screenshot could not be saved. \(underlying)"
+        case .manifestCorrupt:
+            return "This session's file is damaged and cannot be opened."
+        case .pdfCompositionFailed(let reason):
+            return "The PDF could not be built. \(reason)"
+        case .airDropUnavailable:
+            return "AirDrop is not available right now."
+        case .noCommentedReturns:
+            return "None of the returned PDFs have comments on them."
+        }
+    }
+}

Sources/ShotdeckCore/PDF/PDFComposer.swift

@@ -0,0 +1,209 @@
+import AppKit
+import CoreGraphics
+import CoreText
+import Foundation
+import ImageIO
+import os
+
+private let pdfLog = Logger(subsystem: "ai.flowmaster.shotdeck", category: "PDF")
+
+public struct PDFComposer: Sendable {
+    public init() {}
+
+    @discardableResult
+    public func compose(
+        session: CaptureSession,
+        imageURL: (Capture) -> URL,
+        title: String,
+        to outputURL: URL
+    ) throws -> Int {
+        if session.isEmpty {
+            throw ShotdeckError.pdfCompositionFailed(reason: "session has no captures")
+        }
+
+        var loaded: [(Capture, CGImage)] = []
+        loaded.reserveCapacity(session.captures.count)
+        for capture in session.captures {
+            let url = imageURL(capture)
+            if let image = Self.loadCGImage(from: url) {
+                loaded.append((capture, image))
+            } else {
+                pdfLog.error(
+                    "skipping capture \(capture.id.uuidString, privacy: .public) seq \(capture.sequence, privacy: .public): image unreadable at \(url.path, privacy: .public)"
+                )
+            }
+        }
+
+        guard !loaded.isEmpty else {
+            throw ShotdeckError.pdfCompositionFailed(reason: "no readable images in session")
+        }
+
+        let pageCount = loaded.count
+        let tmpURL = outputURL
+            .deletingLastPathComponent()
+            .appendingPathComponent(".tmp-\(UUID().uuidString)-\(outputURL.lastPathComponent)")
+
+        do {
+            try Self.writePDF(
+                loaded: loaded,
+                pageCount: pageCount,
+                title: title,
+                sessionID: session.id,
+                to: tmpURL
+            )
+
+            let handle = try FileHandle(forWritingTo: tmpURL)
+            try handle.synchronize()
+            try handle.close()
+
+            if FileManager.default.fileExists(atPath: outputURL.path) {
+                try FileManager.default.removeItem(at: outputURL)
+            }
+            try FileManager.default.moveItem(at: tmpURL, to: outputURL)
+            return pageCount
+        } catch {
+            try? FileManager.default.removeItem(at: tmpURL)
+            if let shotdeck = error as? ShotdeckError {
+                throw shotdeck
+            }
+            throw ShotdeckError.pdfCompositionFailed(reason: error.localizedDescription)
+        }
+    }
+
+    public static func fileName(for session: CaptureSession) -> String {
+        "Shotdeck-\(DubaiTime.fileStamp(session.createdAt)).pdf"
+    }
+
+    private static func writePDF(
+        loaded: [(Capture, CGImage)],
+        pageCount: Int,
+        title: String,
+        sessionID: UUID,
+        to tmpURL: URL
+    ) throws {
+        guard let consumer = CGDataConsumer(url: tmpURL as CFURL) else {
+            throw ShotdeckError.pdfCompositionFailed(reason: "cannot open output location")
+        }
+
+        let auxiliaryInfo: [String: Any] = [
+            kCGPDFContextCreator as String: "Shotdeck",
+            kCGPDFContextTitle as String: title,
+            kCGPDFContextSubject as String: sessionID.uuidString.lowercased(),
+        ]
+
+        guard let context = CGContext(
+            consumer: consumer,
+            mediaBox: nil,
+            auxiliaryInfo as CFDictionary
+        ) else {
+            throw ShotdeckError.pdfCompositionFailed(reason: "cannot open output location")
+        }
+
+        let lightGrey = CGColor(gray: 0.75, alpha: 1)
+        let black = CGColor(gray: 0, alpha: 1)
+        let timestampColor = CGColor(gray: 0.45, alpha: 1)
+
+        for pageIndex in 1...pageCount {
+            let (capture, cgImage) = loaded[pageIndex - 1]
+            let layout = PageLayout(capture: capture, pageIndex: pageIndex, pageCount: pageCount)
+
+            context.beginPDFPage(Self.pageInfo(mediaBox: layout.pageRect))
+
+            context.draw(cgImage, in: layout.imageRect)
+
+            context.setStrokeColor(lightGrey)
+            context.setLineWidth(0.5)
+            context.move(to: CGPoint(x: layout.headerRect.minX, y: layout.headerRect.minY))
+            context.addLine(to: CGPoint(x: layout.headerRect.maxX, y: layout.headerRect.minY))
+            context.strokePath()
+
+            drawText(
+                layout.pageNumberText,
+                font: layout.pageNumberFont,
+                color: black,
+                at: layout.pageNumberOrigin,
+                in: context
+            )
+            drawText(
+                layout.timestampText,
+                font: layout.timestampFont,
+                color: timestampColor,
+                at: layout.timestampOrigin,
+                in: context
+            )
+            drawText(
+                "PASS",
+                font: layout.tickLabelFont,
+                color: black,
+                at: layout.passLabelOrigin,
+                in: context
+            )
+            drawText(
+                "FAIL",
+                font: layout.tickLabelFont,
+                color: black,
+                at: layout.failLabelOrigin,
+                in: context
+            )
+
+            strokeTickBox(layout.passTickBox, in: context, color: black)
+            strokeTickBox(layout.failTickBox, in: context, color: black)
+
+            context.endPDFPage()
+        }
+
+        context.closePDF()
+    }
+
+    private static func pageInfo(mediaBox: CGRect) -> CFDictionary {
+        var box = mediaBox
+        let data = Data(bytes: &box, count: MemoryLayout<CGRect>.size)
+        return [kCGPDFContextMediaBox as String: data] as CFDictionary
+    }
+
+    private static func drawText(
+        _ string: String,
+        font: NSFont,
+        color: CGColor,
+        at origin: CGPoint,
+        in context: CGContext
+    ) {
+        let attributes: [CFString: Any] = [
+            kCTFontAttributeName: font,
+            kCTForegroundColorAttributeName: color,
+        ]
+        guard let attributed = CFAttributedStringCreate(
+            nil,
+            string as CFString,
+            attributes as CFDictionary
+        ) else {
+            return
+        }
+        let line = CTLineCreateWithAttributedString(attributed)
+        context.textMatrix = .identity
+        context.textPosition = origin
+        CTLineDraw(line, context)
+    }
+
+    private static func strokeTickBox(_ box: CGRect, in context: CGContext, color: CGColor) {
+        let path = CGPath(
+            roundedRect: box,
+            cornerWidth: 2,
+            cornerHeight: 2,
+            transform: nil
+        )
+        context.addPath(path)
+        context.setStrokeColor(color)
+        context.setLineWidth(1.0)
+        context.strokePath()
+    }
+
+    private static func loadCGImage(from url: URL) -> CGImage? {
+        guard let source = CGImageSourceCreateWithURL(url as CFURL, nil),
+              CGImageSourceGetCount(source) > 0
+        else {
+            return nil
+        }
+        return CGImageSourceCreateImageAtIndex(source, 0, nil)
+    }
+}

Sources/ShotdeckCore/PDF/PageLayout.swift

@@ -0,0 +1,149 @@
+import AppKit
+import CoreGraphics
+import CoreText
+import Foundation
+
+public struct PageLayout: Sendable, Equatable {
+    public let isLandscape: Bool
+    public let pageRect: CGRect
+    public let headerRect: CGRect
+    public let imageBoxRect: CGRect
+    public let imageRect: CGRect
+
+    public let pageNumberText: String
+    public let pageNumberOrigin: CGPoint
+    public let timestampText: String
+    public let timestampOrigin: CGPoint
+
+    public let passLabelOrigin: CGPoint
+    public let failLabelOrigin: CGPoint
+    public let passTickBox: CGRect
+    public let failTickBox: CGRect
+
+    /// Constructed at access time so `PageLayout` stays Sendable under Swift 6
+    /// (`NSFont` is not Sendable). Same `NSFont.systemFont` values used for measurement.
+    public var pageNumberFont: NSFont { NSFont.systemFont(ofSize: 9, weight: .semibold) }
+    public var timestampFont: NSFont { NSFont.systemFont(ofSize: 9, weight: .regular) }
+    public var tickLabelFont: NSFont { NSFont.systemFont(ofSize: 8, weight: .semibold) }
+
+    private static let marginAll: CGFloat = 18
+    private static let headerHeight: CGFloat = 26
+    private static let headerImageGap: CGFloat = 10
+    private static let tickBoxSize: CGFloat = 13
+    private static let tickGroupGap: CGFloat = 8
+    private static let portraitPage = CGSize(width: 595, height: 842)
+    private static let landscapePage = CGSize(width: 842, height: 595)
+
+    /// `pageIndex` and `pageCount` are 1-based / total, over ACTUALLY-WRITTEN pages
+    /// (see SPEC decision D-D), not `capture.sequence` / `session.captures.count`.
+    public init(capture: Capture, pageIndex: Int, pageCount: Int) {
+        let pageNumberFont = NSFont.systemFont(ofSize: 9, weight: .semibold)
+        let timestampFont = NSFont.systemFont(ofSize: 9, weight: .regular)
+        let tickLabelFont = NSFont.systemFont(ofSize: 8, weight: .semibold)
+
+        isLandscape = capture.isLandscape
+        pageRect = CGRect(origin: .zero, size: isLandscape ? Self.landscapePage : Self.portraitPage)
+        let W = pageRect.width
+        let H = pageRect.height
+
+        let contentMinX = Self.marginAll
+        let contentMaxX = W - Self.marginAll
+        let contentMinY = Self.marginAll
+        let contentMaxY = H - Self.marginAll
+        let contentWidth = contentMaxX - contentMinX
+
+        headerRect = CGRect(
+            x: contentMinX,
+            y: contentMaxY - Self.headerHeight,
+            width: contentWidth,
+            height: Self.headerHeight
+        )
+
+        imageBoxRect = CGRect(
+            x: contentMinX,
+            y: contentMinY,
+            width: contentWidth,
+            height: headerRect.minY - Self.headerImageGap - contentMinY
+        )
+
+        let pointSize = CGSize(
+            width: CGFloat(capture.pixelWidth) / capture.scale,
+            height: CGFloat(capture.pixelHeight) / capture.scale
+        )
+        let fitScale = min(
+            imageBoxRect.width / pointSize.width,
+            imageBoxRect.height / pointSize.height,
+            1.0
+        )
+        let drawnSize = CGSize(
+            width: pointSize.width * fitScale,
+            height: pointSize.height * fitScale
+        )
+        imageRect = CGRect(
+            x: imageBoxRect.midX - drawnSize.width / 2,
+            y: imageBoxRect.midY - drawnSize.height / 2,
+            width: drawnSize.width,
+            height: drawnSize.height
+        )
+
+        let metricsFont = timestampFont as CTFont
+        let ascent = CTFontGetAscent(metricsFont)
+        let descent = CTFontGetDescent(metricsFont)
+        let baselineY = headerRect.minY + (headerRect.height - (ascent + descent)) / 2 + descent
+
+        pageNumberText = "\(pageIndex) / \(pageCount)"
+        pageNumberOrigin = CGPoint(x: headerRect.minX, y: baselineY)
+
+        timestampText = DubaiTime.stamp(capture.capturedAt)
+        let pageNumberWidth = Self.measuredWidth(pageNumberText, font: pageNumberFont)
+        timestampOrigin = CGPoint(x: headerRect.minX + pageNumberWidth + 10, y: baselineY)
+
+        let groupRightX = headerRect.maxX
+        let failBoxMinX = groupRightX - Self.tickBoxSize
+        let tickBoxY = headerRect.midY - Self.tickBoxSize / 2
+        failTickBox = CGRect(
+            x: failBoxMinX,
+            y: tickBoxY,
+            width: Self.tickBoxSize,
+            height: Self.tickBoxSize
+        )
+
+        let failLabelWidth = Self.measuredWidth("FAIL", font: tickLabelFont)
+        let failLabelMaxX = failTickBox.minX - Self.tickGroupGap
+        failLabelOrigin = CGPoint(x: failLabelMaxX - failLabelWidth, y: baselineY)
+
+        let passBoxMaxX = failLabelOrigin.x - Self.tickGroupGap
+        passTickBox = CGRect(
+            x: passBoxMaxX - Self.tickBoxSize,
+            y: tickBoxY,
+            width: Self.tickBoxSize,
+            height: Self.tickBoxSize
+        )
+
+        let passLabelWidth = Self.measuredWidth("PASS", font: tickLabelFont)
+        let passLabelMaxX = passTickBox.minX - Self.tickGroupGap
+        passLabelOrigin = CGPoint(x: passLabelMaxX - passLabelWidth, y: baselineY)
+    }
+
+    public static func == (lhs: PageLayout, rhs: PageLayout) -> Bool {
+        lhs.isLandscape == rhs.isLandscape
+            && lhs.pageRect == rhs.pageRect
+            && lhs.headerRect == rhs.headerRect
+            && lhs.imageBoxRect == rhs.imageBoxRect
+            && lhs.imageRect == rhs.imageRect
+            && lhs.pageNumberText == rhs.pageNumberText
+            && lhs.pageNumberOrigin == rhs.pageNumberOrigin
+            && lhs.timestampText == rhs.timestampText
+            && lhs.timestampOrigin == rhs.timestampOrigin
+            && lhs.passLabelOrigin == rhs.passLabelOrigin
+            && lhs.failLabelOrigin == rhs.failLabelOrigin
+            && lhs.passTickBox == rhs.passTickBox
+            && lhs.failTickBox == rhs.failTickBox
+    }
+
+    private static func measuredWidth(_ text: String, font: NSFont) -> CGFloat {
+        let attributed = NSAttributedString(string: text, attributes: [.font: font])
+        let line = CTLineCreateWithAttributedString(attributed)
+        return CGFloat(CTLineGetTypographicBounds(line, nil, nil, nil))
+    }
+}

Sources/ShotdeckCore/Returns/AnnotationInspector.swift

@@ -0,0 +1,110 @@
+import Foundation
+import PDFKit
+
+public struct ReturnedDocument: Codable, Sendable, Identifiable, Equatable {
+    public var id: URL { fileURL }
+    public let fileURL: URL
+    /// Session UUID recovered from the PDF's subject attribute, when present and valid.
+    public let sessionID: UUID?
+    public let pageCount: Int
+    /// 1-based page numbers that carry at least one human mark, ascending, no duplicates.
+    public let annotatedPages: [Int]
+    public let detectedAt: Date
+    public var isCommented: Bool { !annotatedPages.isEmpty }
+
+    public init(
+        fileURL: URL,
+        sessionID: UUID?,
+        pageCount: Int,
+        annotatedPages: [Int],
+        detectedAt: Date
+    ) {
+        self.fileURL = fileURL
+        self.sessionID = sessionID
+        self.pageCount = pageCount
+        self.annotatedPages = annotatedPages
+        self.detectedAt = detectedAt
+    }
+}
+
+public enum AnnotationInspector {
+    private static let humanMarkTypes: Set<String> = [
+        PDFAnnotationSubtype.ink.rawValue,
+        PDFAnnotationSubtype.highlight.rawValue,
+        PDFAnnotationSubtype.underline.rawValue,
+        PDFAnnotationSubtype.strikeOut.rawValue,
+        // PDFKit has no PDFAnnotationSubtype.squiggly member (unsupported renderer),
+        // but Apple Markup still writes Adobe /Squiggly objects that we must count.
+        PDFAnnotationSubtype(rawValue: "/Squiggly").rawValue,
+        PDFAnnotationSubtype.freeText.rawValue,
+        PDFAnnotationSubtype.square.rawValue,
+        PDFAnnotationSubtype.circle.rawValue,
+        PDFAnnotationSubtype.line.rawValue,
+        PDFAnnotationSubtype.stamp.rawValue,
+        PDFAnnotationSubtype.text.rawValue,
+    ]
+
+    // .link ignored: a PDF hyperlink is structural, not a human mark.
+    // .popup ignored: it is always the companion of another annotation; counting it
+    //   would double-count a single human mark as two.
+    // .widget ignored: a form field. Shotdeck's own PASS/FAIL boxes are page content
+    //   (drawn by WP-2), never PDFAnnotation objects — a widget seen here can only be
+    //   introduced by a third-party tool flattening/reopening the file, and is not a
+    //   human mark either way.
+
+    /// PDFKit's `PDFAnnotation.type` may omit the leading slash that
+    /// `PDFAnnotationSubtype.rawValue` includes; compare against the slash form.
+    private static func pdfTypeName(_ type: String) -> String {
+        type.hasPrefix("/") ? type : "/" + type
+    }
+
+    private static func isHumanMark(_ annotation: PDFAnnotation) -> Bool {
+        guard let raw = annotation.type else { return false }
+        let type = pdfTypeName(raw)
+        guard humanMarkTypes.contains(type) else { return false }
+        if type == PDFAnnotationSubtype.ink.rawValue {
+            let b = annotation.bounds
+            return b.width > 0 && b.height > 0   // zero-area ink = an undone stroke, not a mark
+        }
+        return true
+    }
+
+    /// Opens the PDF at fileURL and reports which pages carry a genuine human mark.
+    /// Throws ShotdeckError.manifestCorrupt(path: fileURL.path) if PDFDocument cannot open it.
+    /// File modification date is never consulted; only persisted PDFAnnotation objects count.
+    public static func inspect(fileURL: URL) throws -> ReturnedDocument {
+        guard let document = PDFDocument(url: fileURL) else {
+            throw ShotdeckError.manifestCorrupt(path: fileURL.path)
+        }
+        var annotatedPages: [Int] = []
+        for index in 0..<document.pageCount {
+            guard let page = document.page(at: index) else { continue }
+            if page.annotations.contains(where: isHumanMark) {
+                annotatedPages.append(index + 1)   // 1-based
+            }
+        }
+        var sessionID: UUID?
+        if let subject = document.documentAttributes?[PDFDocumentAttribute.subjectAttribute] as? String {
+            sessionID = UUID(uuidString: subject)   // nil (not thrown) if it doesn't parse
+        }
+        return ReturnedDocument(
+            fileURL: fileURL, sessionID: sessionID, pageCount: document.pageCount,
+            annotatedPages: annotatedPages, detectedAt: Date()
+        )
+    }
+
+    /// True when this PDF was produced by Shotdeck. Creator attribute is authoritative;
+    /// the filename fallback applies ONLY when the creator attribute is absent.
+    public static func isShotdeckDocument(_ document: PDFDocument) -> Bool {
+        if let creator = document.documentAttributes?[PDFDocumentAttribute.creatorAttribute] as? String {
+            return creator == "Shotdeck"          // present creator is authoritative, full stop
+        }
+        // Creator ABSENT (some apps rewrite metadata on save) -> filename fallback only here.
+        guard let name = document.documentURL?.lastPathComponent else { return false }
+        // .lastPathComponent on a file URL is already percent-decoded; do not use .absoluteString.
+        return name.wholeMatch(of: /^Shotdeck-\d{8}-\d{6}( \d+)?\.pdf$/) != nil
+        // Case-sensitive by construction (Swift Regex literals are case-sensitive by default).
+        // The optional "( \d+)?" is macOS's duplicate-name suffix AirDrop adds when a file of
+        // the same name already exists in the watch folder — the normal case for a return.
+    }
+}

Sources/ShotdeckCore/Returns/ReturnLedger.swift

@@ -0,0 +1,60 @@
+import Foundation
+
+public actor ReturnLedger {
+    private let fileURL: URL
+    private var entries: [URL: ReturnedDocument]
+
+    /// Loads `returns.json` under paths.root if it exists; starts empty otherwise.
+    /// A file that cannot be decoded is renamed (never deleted) and the ledger starts empty.
+    public init(paths: AppSupportPaths) throws {
+        self.fileURL = paths.root.appendingPathComponent("returns.json")
+        if FileManager.default.fileExists(atPath: fileURL.path) {
+            let data = try Data(contentsOf: fileURL)
+            do {
+                let decoded = try JSONDecoder().decode([ReturnedDocument].self, from: data)
+                entries = Dictionary(decoded.map { ($0.fileURL, $0) }, uniquingKeysWith: { _, new in new })
+            } catch {
+                let stamp = DubaiTime.fileStamp(Date())
+                let corruptURL = fileURL.deletingLastPathComponent()
+                    .appendingPathComponent("returns.json.corrupt-\(stamp)")
+                try FileManager.default.moveItem(at: fileURL, to: corruptURL)
+                Log.returns.error(
+                    "returns.json could not be decoded; moved to \(corruptURL.path, privacy: .public): \(error.localizedDescription, privacy: .public)"
+                )
+                entries = [:]
+            }
+        } else {
+            entries = [:]
+        }
+    }
+
+    /// Upserts by fileURL — recording the same URL again replaces the prior entry
+    /// (the most recently recorded call wins, regardless of its detectedAt value).
+    public func record(_ document: ReturnedDocument) throws {
+        entries[document.fileURL] = document
+        try persist()
+    }
+
+    /// Every recorded return, newest detectedAt first.
+    public func all() throws -> [ReturnedDocument] {
+        entries.values.sorted { $0.detectedAt > $1.detectedAt }
+    }
+
+    /// Commented returns (isCommented == true), newest detectedAt first.
+    public func commented() throws -> [ReturnedDocument] {
+        try all().filter(\.isCommented)
+    }
+
+    /// Absolute POSIX paths of commented returns, newest first, one per line, no
+    /// trailing newline. Throws ShotdeckError.noCommentedReturns when commented() is empty.
+    public func clipboardText() throws -> String {
+        let paths = try commented().map { $0.fileURL.path }
+        guard !paths.isEmpty else { throw ShotdeckError.noCommentedReturns }
+        return paths.joined(separator: "\n")
+    }
+
+    private func persist() throws {
+        let data = try JSONEncoder().encode(Array(entries.values))
+        try AtomicFile.write(data, to: fileURL)
+    }
+}

Sources/ShotdeckCore/Returns/ReturnWatcher.swift

@@ -0,0 +1,154 @@
+import Foundation
+import PDFKit
+import CoreServices   // FSEventStream* APIs; system framework, no Package.swift change needed
+
+public actor ReturnWatcher {
+    private let ledger: ReturnLedger
+    private var watchFolder: URL
+    private var onChange: (@Sendable ([ReturnedDocument]) -> Void)?
+    private var stream: FSEventStreamRef?
+    private var bridge: FSEventBridge?
+    private var pendingScanTask: Task<Void, Never>?
+    private let eventQueue = DispatchQueue(label: "ai.flowmaster.shotdeck.returns.fsevents")
+
+    /// Watch folder is `paths.watchFolder`, which production constructs from
+    /// `FolderSettings.resolve().watch`. This type never calls FolderSettings;
+    /// `updateWatchFolder` is invoked by the UI layer only.
+    public init(paths: AppSupportPaths, ledger: ReturnLedger) {
+        self.ledger = ledger
+        self.watchFolder = paths.watchFolder   // never a literal "~/Downloads" here
+    }
+
+    /// Starts watching paths.watchFolder for returned PDFs. Performs one immediate
+    /// scanNow() before returning, then calls onChange after every subsequent debounced
+    /// batch (even if that batch's result is empty — the caller decides what to do).
+    public func start(onChange: @escaping @Sendable ([ReturnedDocument]) -> Void) async throws {
+        self.onChange = onChange
+        try startStream(on: watchFolder)
+        let found = try await scanNow()
+        onChange(found)
+    }
+
+    /// Idempotent. Stops and releases the FSEventStream if one is running; safe to call
+    /// when never started or already stopped. Cancels any pending debounced scan.
+    public func stop() {
+        // Idempotent: nil stream / already-stopped is a no-op; never started is the same.
+        pendingScanTask?.cancel()
+        pendingScanTask = nil
+        if let stream {
+            FSEventStreamStop(stream)
+            FSEventStreamInvalidate(stream)
+            FSEventStreamRelease(stream)
+        }
+        stream = nil
+        bridge = nil
+    }
+
+    /// Called by whoever owns the Settings "Choose..." folder action (WP-4c) after the user
+    /// picks a new watch folder. If the watcher was running, stops the old FSEventStream,
+    /// switches to the new folder, restarts, and performs one immediate scanNow (reporting
+    /// through the same onChange callback given to start()). If the watcher was never
+    /// started, only updates the stored folder for the next start() call.
+    public func updateWatchFolder(_ url: URL) async throws {
+        let wasRunning = stream != nil
+        stop()
+        watchFolder = url
+        guard wasRunning else { return }
+        try startStream(on: url)
+        let found = try await scanNow()
+        onChange?(found)
+    }
+
+    /// Scans the watch folder once, immediately, without waiting for an event. Every
+    /// recognized, stable, openable Shotdeck PDF present is (re-)inspected and (re-)recorded
+    /// into the ledger; returns exactly the documents processed in this call.
+    @discardableResult
+    public func scanNow() async throws -> [ReturnedDocument] {
+        let fm = FileManager.default
+        let candidates = (try? fm.contentsOfDirectory(
+            at: watchFolder, includingPropertiesForKeys: nil
+        )) ?? []
+        var results: [ReturnedDocument] = []
+        for url in candidates.sorted(by: { $0.lastPathComponent < $1.lastPathComponent }) {
+            let name = url.lastPathComponent
+            // ".pdf.inprogress" already fails hasSuffix(".pdf") -> naturally skipped.
+            guard name.hasSuffix(".pdf"), !name.hasPrefix(".") else { continue }
+            guard await isStableAndReadable(url) else { continue }   // leave for next event
+            guard let document = PDFDocument(url: url),
+                  AnnotationInspector.isShotdeckDocument(document) else { continue }
+            guard let inspected = try? AnnotationInspector.inspect(fileURL: url) else { continue }
+            try await ledger.record(inspected)
+            results.append(inspected)
+        }
+        return results
+    }
+
+    /// Size-stable: two equal byte counts 250 ms apart AND PDFDocument opens;
+    /// otherwise leave the file for the next event.
+    private func isStableAndReadable(_ url: URL) async -> Bool {
+        let fm = FileManager.default
+        guard let size1 = try? fm.attributesOfItem(atPath: url.path)[.size] as? Int else { return false }
+        try? await Task.sleep(for: .milliseconds(250))
+        guard let size2 = try? fm.attributesOfItem(atPath: url.path)[.size] as? Int else { return false }
+        guard size1 == size2, size1 > 0 else { return false }
+        return PDFDocument(url: url) != nil
+    }
+
+    private func startStream(on folder: URL) throws {
+        let bridge = FSEventBridge { [weak self] in
+            guard let self else { return }
+            Task { await self.scheduleDebouncedScan() }
+        }
+        self.bridge = bridge
+        var context = FSEventStreamContext()
+        context.version = 0
+        context.info = Unmanaged.passUnretained(bridge).toOpaque()
+        context.retain = nil
+        context.release = nil
+        context.copyDescription = nil
+        guard let stream = FSEventStreamCreate(
+            kCFAllocatorDefault, shotdeckFSEventsCallback, &context,
+            [folder.path] as CFArray, FSEventStreamEventId(kFSEventStreamEventIdSinceNow),
+            0.0,
+            FSEventStreamCreateFlags(kFSEventStreamCreateFlagFileEvents | kFSEventStreamCreateFlagNoDefer)
+        ) else {
+            throw ShotdeckError.captureFailed(underlying: "could not create FSEventStream for \(folder.path)")
+        }
+        // Dispatch queue, not a run loop: this actor has no run loop of its own, and
+        // FSEventStreamSetDispatchQueue is the modern replacement for
+        // FSEventStreamScheduleWithRunLoop. One dedicated serial queue per watcher.
+        FSEventStreamSetDispatchQueue(stream, eventQueue)
+        guard FSEventStreamStart(stream) else {
+            FSEventStreamInvalidate(stream)
+            FSEventStreamRelease(stream)
+            throw ShotdeckError.captureFailed(underlying: "FSEventStreamStart failed for \(folder.path)")
+        }
+        self.stream = stream
+    }
+
+    private func scheduleDebouncedScan() async {
+        pendingScanTask?.cancel()
+        pendingScanTask = Task {
+            try? await Task.sleep(for: .milliseconds(400))   // coalesce AirDrop's write+rename burst
+            guard !Task.isCancelled else { return }
+            guard let found = try? await self.scanNow() else { return }
+            // One in-flight debounced callback may land after stop(); it is a
+            // harmless read-only rescan (ledger upsert, no watch-folder mutation).
+            self.onChange?(found)
+        }
+    }
+}
+
+/// Non-actor bridge because FSEventStreamCallback is a @convention(c) function pointer and
+/// cannot capture actor-isolated state directly; it hops back onto the actor via Task.
+private final class FSEventBridge: @unchecked Sendable {
+    // @unchecked is safe: `notify` is a let, set once at init, never mutated after — the
+    // type is immutable for its entire lifetime.
+    let notify: @Sendable () -> Void
+    init(notify: @escaping @Sendable () -> Void) { self.notify = notify }
+}
+
+private let shotdeckFSEventsCallback: FSEventStreamCallback = { _, info, _, _, _, _ in
+    guard let info else { return }
+    Unmanaged<FSEventBridge>.fromOpaque(info).takeUnretainedValue().notify()
+}

Sources/ShotdeckCore/Spool/SpoolStore.swift

@@ -0,0 +1,418 @@
+import Foundation
+import ImageIO
+import CoreGraphics
+import Darwin
+
+public actor SpoolStore {
+    private let paths: AppSupportPaths
+    private var openSession: CaptureSession
+
+    public init(paths: AppSupportPaths) throws {
+        self.paths = paths
+        let fm = FileManager.default
+        try Self.supersedeSpoolArchiveOverlaps(paths: paths, fileManager: fm)
+        try Self.finishInterruptedArchives(paths: paths, fileManager: fm)
+        let remainingIDs = try Self.listUUIDDirectories(in: paths.spool, fileManager: fm)
+        if remainingIDs.isEmpty {
+            self.openSession = try Self.createFreshSession(paths: paths)
+        } else {
+            var candidates: [CaptureSession] = []
+            for id in remainingIDs {
+                let dir = paths.sessionDirectory(id)
+                candidates.append(
+                    try Self.reconcileSessionDirectory(
+                        at: dir, id: id, assumedStateIfRebuilt: .open, fileManager: fm))
+            }
+            self.openSession = Self.pickNewest(first: candidates[0], rest: Array(candidates.dropFirst()))
+        }
+    }
+
+    /// The session currently accepting captures. Cheap accessor — all reconciliation already
+    /// happened once, inside init.
+    public func currentSession() throws -> CaptureSession {
+        openSession
+    }
+
+    /// Writes `pngData` to disk and fsyncs it BEFORE the manifest is touched, then updates and
+    /// durably writes the manifest. Order is non-negotiable: image durable -> manifest durable
+    /// -> return. Uses AtomicFile.write/writeJSON for both writes — never Data.write(to:).
+    public func append(
+        pngData: Data, pixelWidth: Int, pixelHeight: Int,
+        scale: CGFloat, capturedAt: Date
+    ) throws -> Capture {
+        let captureID = UUID()
+        let sequence = openSession.nextSequence
+        let fileName = "\(String(format: "%03d", sequence))-\(Self.hexSuffix(captureID)).png"
+        let sessionDir = paths.sessionDirectory(openSession.id)
+        let fileURL = sessionDir.appendingPathComponent(fileName)
+        try AtomicFile.write(pngData, to: fileURL)
+        let capture = Capture(
+            id: captureID, sequence: sequence, fileName: fileName,
+            pixelWidth: pixelWidth, pixelHeight: pixelHeight,
+            scale: scale, capturedAt: capturedAt)
+        let updated = openSession.appending(capture)
+        try AtomicFile.writeJSON(updated, to: sessionDir.appendingPathComponent("session.json"))
+        openSession = updated
+        return capture
+    }
+
+    /// D-11: moves the capture's PNG into `<sessionDir>/removed/` (created lazily) and drops
+    /// its manifest entry. NEVER unlinks/deletes a user PNG. Throws (no filesystem change) if
+    /// `captureID` is not present in the open session.
+    public func remove(captureID: UUID) throws -> CaptureSession {
+        guard let capture = openSession.captures.first(where: { $0.id == captureID }) else {
+            throw ShotdeckError.spoolWriteFailed(
+                path: paths.sessionDirectory(openSession.id).path,
+                underlying: "capture \(captureID) is not in the open session")
+        }
+        let sessionDir = paths.sessionDirectory(openSession.id)
+        let removedDir = sessionDir.appendingPathComponent("removed", isDirectory: true)
+        do {
+            try FileManager.default.createDirectory(at: removedDir, withIntermediateDirectories: true)
+        } catch {
+            throw ShotdeckError.spoolWriteFailed(path: removedDir.path, underlying: error.localizedDescription)
+        }
+        let sourceURL = sessionDir.appendingPathComponent(capture.fileName)
+        let destURL = removedDir.appendingPathComponent(capture.fileName)
+        guard rename(sourceURL.path, destURL.path) == 0 else {
+            throw ShotdeckError.spoolWriteFailed(
+                path: destURL.path,
+                underlying: "could not move the capture into removed/: \(String(cString: strerror(errno)))")
+        }
+        try AtomicFile.fsyncDirectory(at: removedDir)
+        let updated = openSession.removing(captureID: captureID)
+        try AtomicFile.writeJSON(updated, to: sessionDir.appendingPathComponent("session.json"))
+        openSession = updated
+        return updated
+    }
+
+    /// Closes the open session (must be non-empty), moves its directory under archive/, records
+    /// pdfFileName, and starts a fresh empty open session. Returns the archived one.
+    public func archiveCurrent(pdfFileName: String) throws -> CaptureSession {
+        guard !openSession.isEmpty else {
+            throw ShotdeckError.spoolWriteFailed(
+                path: paths.sessionDirectory(openSession.id).path,
+                underlying: "cannot archive an empty session")
+        }
+        let archived = openSession.markArchived(pdfFileName: pdfFileName)
+        let sessionDir = paths.sessionDirectory(openSession.id)
+        try AtomicFile.writeJSON(archived, to: sessionDir.appendingPathComponent("session.json"))
+        let archiveDir = paths.archiveDirectory(openSession.id)
+        guard rename(sessionDir.path, archiveDir.path) == 0 else {
+            throw ShotdeckError.spoolWriteFailed(
+                path: sessionDir.path,
+                underlying: "could not move the session into archive/: \(String(cString: strerror(errno)))")
+        }
+        try AtomicFile.fsyncDirectory(at: paths.archive)
+        let fresh = try Self.createFreshSession(paths: paths)
+        openSession = fresh
+        return archived
+    }
+
+    /// Abandons the open session only if it is empty (mints a new id/dir/manifest); throws,
+    /// with no filesystem change, if the open session has captures.
+    public func startNewSession() throws -> CaptureSession {
+        guard openSession.isEmpty else {
+            throw ShotdeckError.spoolWriteFailed(
+                path: paths.sessionDirectory(openSession.id).path,
+                underlying: "cannot start a new session: \(openSession.captures.count) capture(s) present in the open session")
+        }
+        let fresh = try Self.createFreshSession(paths: paths)
+        openSession = fresh
+        return fresh
+    }
+
+    /// Absolute URL of a capture's PNG, in whichever top-level directory its session lives
+    /// (spool/ if session.state == .open, archive/ if .archived).
+    public func imageURL(for capture: Capture, in session: CaptureSession) -> URL {
+        let dir = session.state == .open ? paths.sessionDirectory(session.id) : paths.archiveDirectory(session.id)
+        return dir.appendingPathComponent(capture.fileName)
+    }
+
+    /// Archived sessions, newest createdAt first. Lazily reconciles each archive/ directory
+    /// the same way init reconciles spool/ candidates (orphan recovery, missing-drop, corrupt
+    /// rebuild) — an archived session's manifest can degrade too and must self-heal without
+    /// ever losing a PNG.
+    public func archivedSessions() throws -> [CaptureSession] {
+        let ids = try Self.listUUIDDirectories(in: paths.archive, fileManager: .default)
+        var sessions: [CaptureSession] = []
+        for id in ids {
+            sessions.append(
+                try Self.reconcileSessionDirectory(
+                    at: paths.archiveDirectory(id), id: id, assumedStateIfRebuilt: .archived, fileManager: .default))
+        }
+        return sessions.sorted { ($0.createdAt, $0.id.uuidString) > ($1.createdAt, $1.id.uuidString) }
+    }
+
+    // MARK: - Reconciliation (static so they can run inside init)
+
+    private static func listUUIDDirectories(in parent: URL, fileManager: FileManager) throws -> [UUID] {
+        let entries: [URL]
+        do {
+            entries = try fileManager.contentsOfDirectory(
+                at: parent,
+                includingPropertiesForKeys: [.isDirectoryKey],
+                options: [])
+        } catch {
+            throw ShotdeckError.spoolWriteFailed(path: parent.path, underlying: error.localizedDescription)
+        }
+        var ids: [UUID] = []
+        for url in entries {
+            let isDirectory = (try? url.resourceValues(forKeys: [.isDirectoryKey]).isDirectory) ?? false
+            guard isDirectory else { continue }
+            if let id = UUID(uuidString: url.lastPathComponent) {
+                ids.append(id)
+            }
+        }
+        return ids
+    }
+
+    private static func supersedeSpoolArchiveOverlaps(paths: AppSupportPaths, fileManager: FileManager) throws {
+        let spoolIDs = Set(try listUUIDDirectories(in: paths.spool, fileManager: fileManager))
+        let archiveIDs = Set(try listUUIDDirectories(in: paths.archive, fileManager: fileManager))
+        for id in spoolIDs.intersection(archiveIDs) {
+            let spoolDir = paths.sessionDirectory(id)
+            let supersededDir = paths.spool.appendingPathComponent(
+                "\(id.uuidString).superseded-\(DubaiTime.fileStamp(Date()))", isDirectory: true)
+            guard rename(spoolDir.path, supersededDir.path) == 0 else {
+                throw ShotdeckError.spoolWriteFailed(
+                    path: spoolDir.path,
+                    underlying: "could not supersede a duplicate spool copy: \(String(cString: strerror(errno)))")
+            }
+            try AtomicFile.fsyncDirectory(at: paths.spool)
+            Log.spool.warning("Found session \(id.uuidString, privacy: .public) in both spool/ and archive/; kept the archive copy and superseded the spool copy — nothing was deleted.")
+        }
+    }
+
+    private static func finishInterruptedArchives(paths: AppSupportPaths, fileManager: FileManager) throws {
+        for id in try listUUIDDirectories(in: paths.spool, fileManager: fileManager) {
+            let spoolDir = paths.sessionDirectory(id)
+            let manifestURL = spoolDir.appendingPathComponent("session.json")
+            guard let data = try? Data(contentsOf: manifestURL),
+                  let decoded = try? decodeSession(from: data),
+                  decoded.id == id, decoded.state == .archived
+            else { continue }
+            let archiveDir = paths.archiveDirectory(id)
+            guard rename(spoolDir.path, archiveDir.path) == 0 else {
+                throw ShotdeckError.spoolWriteFailed(
+                    path: spoolDir.path,
+                    underlying: "could not complete an interrupted archive move: \(String(cString: strerror(errno)))")
+            }
+            try AtomicFile.fsyncDirectory(at: paths.archive)
+            Log.spool.warning("Completed an archive move for \(id.uuidString, privacy: .public) that was interrupted before this launch.")
+        }
+    }
+
+    private static func reconcileSessionDirectory(
+        at dir: URL,
+        id: UUID,
+        assumedStateIfRebuilt: SessionState,
+        fileManager: FileManager
+    ) throws -> CaptureSession {
+        let manifestURL = dir.appendingPathComponent("session.json")
+        let decoded: CaptureSession?
+        if let data = try? Data(contentsOf: manifestURL),
+           let session = try? decodeSession(from: data),
+           session.id == id {
+            decoded = session
+        } else {
+            decoded = nil
+        }
+
+        guard let session = decoded else {
+            return try rebuildManifest(
+                at: dir,
+                id: id,
+                assumedState: assumedStateIfRebuilt,
+                fileManager: fileManager)
+        }
+
+        var present: [Capture] = []
+        var missingCount = 0
+        for capture in session.captures {
+            let fileURL = dir.appendingPathComponent(capture.fileName)
+            if fileManager.fileExists(atPath: fileURL.path) {
+                present.append(capture)
+            } else {
+                missingCount += 1
+            }
+        }
+        let referenced = Set(session.captures.map(\.fileName))
+        let pngs = try listCapturePNGs(in: dir, fileManager: fileManager)
+        var recoveredOrphans: [Capture] = []
+        for pngURL in pngs where !referenced.contains(pngURL.lastPathComponent) {
+            if let recovered = recoverCapture(from: pngURL, fileManager: fileManager) {
+                recoveredOrphans.append(recovered)
+            } else {
+                Log.spool.error("Could not decode orphan PNG at \(pngURL.path, privacy: .public); leaving it on disk.")
+            }
+        }
+        let deletedTmp = deleteStrayTmpFiles(in: dir, fileManager: fileManager)
+        if missingCount == 0 && recoveredOrphans.isEmpty && !deletedTmp {
+            return session
+        }
+        let finalCaptures = (present + recoveredOrphans).sorted { $0.sequence < $1.sequence }
+        let updated = CaptureSession(
+            id: session.id,
+            createdAt: session.createdAt,
+            state: session.state,
+            captures: finalCaptures,
+            pdfFileName: session.pdfFileName)
+        try AtomicFile.writeJSON(updated, to: manifestURL)
+        Log.spool.warning("Reconciled session \(id.uuidString, privacy: .public): dropped \(missingCount) missing PNG(s), recovered \(recoveredOrphans.count) orphan(s).")
+        return updated
+    }
+
+    private static func rebuildManifest(
+        at dir: URL,
+        id: UUID,
+        assumedState: SessionState,
+        fileManager: FileManager
+    ) throws -> CaptureSession {
+        let manifestURL = dir.appendingPathComponent("session.json")
+        if fileManager.fileExists(atPath: manifestURL.path) {
+            let corruptURL = dir.appendingPathComponent(
+                "session.json.corrupt-\(DubaiTime.fileStamp(Date()))")
+            do {
+                try fileManager.moveItem(at: manifestURL, to: corruptURL)
+            } catch {
+                throw ShotdeckError.spoolWriteFailed(
+                    path: manifestURL.path,
+                    underlying: "could not quarantine a corrupt manifest: \(error.localizedDescription)")
+            }
+        }
+
+        var recovered: [Capture] = []
+        for pngURL in try listCapturePNGs(in: dir, fileManager: fileManager) {
+            if let capture = recoverCapture(from: pngURL, fileManager: fileManager) {
+                recovered.append(capture)
+            } else {
+                Log.spool.error("Could not decode PNG at \(pngURL.path, privacy: .public) while rebuilding the manifest; leaving it on disk.")
+            }
+        }
+        _ = deleteStrayTmpFiles(in: dir, fileManager: fileManager)
+        recovered.sort { $0.sequence < $1.sequence }
+
+        let createdAt: Date
+        if let earliest = recovered.map(\.capturedAt).min() {
+            createdAt = earliest
+        } else {
+            createdAt = (try? dir.resourceValues(forKeys: [.creationDateKey]))?.creationDate ?? Date()
+        }
+
+        let rebuilt = CaptureSession(
+            id: id,
+            createdAt: createdAt,
+            state: assumedState,
+            captures: recovered,
+            pdfFileName: nil)
+        try AtomicFile.writeJSON(rebuilt, to: dir.appendingPathComponent("session.json"))
+        Log.spool.warning("Rebuilt manifest for \(id.uuidString, privacy: .public) from \(recovered.count) recovered PNG(s).")
+        if assumedState == .archived {
+            Log.spool.warning("Rebuilt an archived session \(id.uuidString, privacy: .public) from PNGs; pdfFileName could not be recovered.")
+        }
+        return rebuilt
+    }
+
+    private static func recoverCapture(from fileURL: URL, fileManager: FileManager) -> Capture? {
+        guard fileManager.fileExists(atPath: fileURL.path) else { return nil }
+        guard let source = CGImageSourceCreateWithURL(fileURL as CFURL, nil),
+              let properties = CGImageSourceCopyPropertiesAtIndex(source, 0, nil) as NSDictionary?,
+              let width = (properties[kCGImagePropertyPixelWidth] as? NSNumber)?.intValue,
+              let height = (properties[kCGImagePropertyPixelHeight] as? NSNumber)?.intValue
+        else { return nil }
+        let name = fileURL.lastPathComponent
+        let sequence = Int(name.prefix(3)) ?? 1
+        let capturedAt = (try? fileURL.resourceValues(forKeys: [.creationDateKey]))?.creationDate ?? Date()
+        return Capture(
+            id: UUID(),
+            sequence: sequence,
+            fileName: name,
+            pixelWidth: width,
+            pixelHeight: height,
+            scale: 1.0,
+            capturedAt: capturedAt)
+    }
+
+    private static func pickNewest(first: CaptureSession, rest: [CaptureSession]) -> CaptureSession {
+        rest.reduce(first) { current, candidate in
+            let currentKey = (current.createdAt, current.id.uuidString)
+            let candidateKey = (candidate.createdAt, candidate.id.uuidString)
+            return candidateKey > currentKey ? candidate : current
+        }
+    }
+
+    private static func createFreshSession(paths: AppSupportPaths) throws -> CaptureSession {
+        let id = UUID()
+        let createdAt = Date()
+        let dir = paths.sessionDirectory(id)
+        do {
+            try FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+        } catch {
+            throw ShotdeckError.spoolWriteFailed(path: dir.path, underlying: error.localizedDescription)
+        }
+        let session = CaptureSession(id: id, createdAt: createdAt, state: .open, captures: [], pdfFileName: nil)
+        try AtomicFile.writeJSON(session, to: dir.appendingPathComponent("session.json"))
+        return session
+    }
+
+    private static func hexSuffix(_ id: UUID) -> String {
+        String(id.uuidString.replacingOccurrences(of: "-", with: "").prefix(8)).uppercased()
+    }
+
+    private static func decodeSession(from data: Data) throws -> CaptureSession {
+        let decoder = JSONDecoder()
+        decoder.dateDecodingStrategy = .iso8601
+        return try decoder.decode(CaptureSession.self, from: data)
+    }
+
+    private static func isCapturePNGName(_ name: String) -> Bool {
+        guard name.hasSuffix(".png") else { return false }
+        let stem = String(name.dropLast(4))
+        let parts = stem.split(separator: "-", maxSplits: 1, omittingEmptySubsequences: false)
+        guard parts.count == 2,
+              parts[0].count == 3,
+              parts[0].allSatisfy(\.isNumber),
+              parts[1].count == 8,
+              parts[1].allSatisfy(\.isHexDigit)
+        else { return false }
+        return true
+    }
+
+    private static func listCapturePNGs(in dir: URL, fileManager: FileManager) throws -> [URL] {
+        let entries: [URL]
+        do {
+            entries = try fileManager.contentsOfDirectory(
+                at: dir,
+                includingPropertiesForKeys: [.isDirectoryKey],
+                options: [])
+        } catch {
+            throw ShotdeckError.spoolWriteFailed(path: dir.path, underlying: error.localizedDescription)
+        }
+        return entries.filter { url in
+            let isDirectory = (try? url.resourceValues(forKeys: [.isDirectoryKey]).isDirectory) ?? false
+            guard !isDirectory else { return false }
+            return isCapturePNGName(url.lastPathComponent)
+        }
+    }
+
+    private static func deleteStrayTmpFiles(in dir: URL, fileManager: FileManager) -> Bool {
+        let entries = (try? fileManager.contentsOfDirectory(
+            at: dir,
+            includingPropertiesForKeys: [.isDirectoryKey],
+            options: [])) ?? []
+        var deleted = false
+        for url in entries {
+            guard url.lastPathComponent.hasSuffix(".tmp") else { continue }
+            let isDirectory = (try? url.resourceValues(forKeys: [.isDirectoryKey]).isDirectory) ?? false
+            guard !isDirectory else { continue }
+            do {
+                try fileManager.removeItem(at: url)
+                deleted = true
+            } catch {
+                Log.spool.error("Could not remove stray temp file at \(url.path, privacy: .public): \(error.localizedDescription, privacy: .public)")
+            }
+        }
+        return deleted
+    }
+}

Sources/ShotdeckCore/Support/AppSupportPaths.swift

@@ -0,0 +1,65 @@
+import Foundation
+
+/// The only type in the app that knows the on-disk directory layout.
+public struct AppSupportPaths: Sendable {
+    public let root: URL
+    public let spool: URL
+    public let archive: URL
+    public let outbox: URL
+    public let watchFolder: URL
+
+    /// Production paths.
+    public static func standard() throws -> AppSupportPaths {
+        let fileManager = FileManager.default
+        let appSupportParent = try fileManager.url(
+            for: .applicationSupportDirectory,
+            in: .userDomainMask,
+            appropriateFor: nil,
+            create: true
+        )
+        let desktop = try fileManager.url(
+            for: .desktopDirectory,
+            in: .userDomainMask,
+            appropriateFor: nil,
+            create: true
+        )
+        let downloads = try fileManager.url(
+            for: .downloadsDirectory,
+            in: .userDomainMask,
+            appropriateFor: nil,
+            create: true
+        )
+        let root = appSupportParent.appendingPathComponent("Shotdeck", isDirectory: true)
+        return try AppSupportPaths(root: root, outbox: desktop, watchFolder: downloads)
+    }
+
+    /// Test paths rooted anywhere. Every directory is created if missing.
+    public init(root: URL, outbox: URL, watchFolder: URL) throws {
+        self.root = root
+        self.spool = root.appendingPathComponent("spool", isDirectory: true)
+        self.archive = root.appendingPathComponent("archive", isDirectory: true)
+        self.outbox = outbox
+        self.watchFolder = watchFolder
+
+        try Self.createDirectory(self.root)
+        try Self.createDirectory(self.spool)
+        try Self.createDirectory(self.archive)
+        try Self.createDirectory(self.outbox)
+        try Self.createDirectory(self.watchFolder)
+    }
+
+    public func sessionDirectory(_ id: UUID) -> URL {
+        spool.appendingPathComponent(id.uuidString, isDirectory: true)
+    }
+
+    public func archiveDirectory(_ id: UUID) -> URL {
+        archive.appendingPathComponent(id.uuidString, isDirectory: true)
+    }
+
+    private static func createDirectory(_ url: URL) throws {
+        try FileManager.default.createDirectory(
+            at: url,
+            withIntermediateDirectories: true
+        )
+    }
+}

Sources/ShotdeckCore/Support/AtomicFile.swift

@@ -0,0 +1,104 @@
+import Foundation
+import Darwin
+
+public enum AtomicFile {
+    /// Writes `data` to `url` durably: writes to `<url>.tmp` in the SAME directory as `url`,
+    /// fsyncs that file descriptor, closes it, rename()s it onto `url` (atomic same-volume
+    /// rename), then opens `url`'s containing directory and fsyncs THAT too (a rename is only
+    /// durable once its directory entry is flushed). Never uses `Data.write(to:)` — that call
+    /// does not fsync.
+    public static func write(_ data: Data, to url: URL) throws {
+        let finalPath = url.path
+        let directoryURL = url.deletingLastPathComponent()
+        let tmpURL = directoryURL.appendingPathComponent(url.lastPathComponent + ".tmp")
+        let tmpPath = tmpURL.path
+
+        // Clear a stale .tmp left by a previous crash. ENOENT (nothing to clear) is fine.
+        if unlink(tmpPath) != 0 && errno != ENOENT {
+            throw ShotdeckError.spoolWriteFailed(
+                path: finalPath,
+                underlying: "could not clear a stale temp file: \(String(cString: strerror(errno)))")
+        }
+
+        let fd = open(tmpPath, O_WRONLY | O_CREAT | O_TRUNC, 0o644)
+        guard fd >= 0 else {
+            throw ShotdeckError.spoolWriteFailed(
+                path: finalPath, underlying: "open failed: \(String(cString: strerror(errno)))")
+        }
+
+        var writeFailure: String?
+        data.withUnsafeBytes { (raw: UnsafeRawBufferPointer) in
+            var remaining = raw.count
+            var pointer = raw.baseAddress
+            while remaining > 0 {
+                let n = Darwin.write(fd, pointer, remaining)
+                if n < 0 {
+                    if errno == EINTR { continue }
+                    writeFailure = "write failed: \(String(cString: strerror(errno)))"
+                    break
+                }
+                if n == 0 { break }
+                remaining -= n
+                pointer = pointer?.advanced(by: n)
+            }
+        }
+        if let writeFailure {
+            close(fd)
+            _ = unlink(tmpPath)
+            throw ShotdeckError.spoolWriteFailed(path: finalPath, underlying: writeFailure)
+        }
+        if fsync(fd) != 0 {
+            let message = "fsync failed: \(String(cString: strerror(errno)))"
+            close(fd)
+            _ = unlink(tmpPath)
+            throw ShotdeckError.spoolWriteFailed(path: finalPath, underlying: message)
+        }
+        if close(fd) != 0 {
+            _ = unlink(tmpPath)
+            throw ShotdeckError.spoolWriteFailed(
+                path: finalPath, underlying: "close failed: \(String(cString: strerror(errno)))")
+        }
+        if rename(tmpPath, finalPath) != 0 {
+            let message = "rename failed: \(String(cString: strerror(errno)))"
+            _ = unlink(tmpPath)
+            throw ShotdeckError.spoolWriteFailed(path: finalPath, underlying: message)
+        }
+        try fsyncDirectory(at: directoryURL)
+    }
+
+    /// Encodes `value` with `JSONEncoder` (`.sortedKeys, .prettyPrinted`,
+    /// `.dateEncodingStrategy = .iso8601`) and writes it through `write(_:to:)`.
+    public static func writeJSON<T: Encodable>(_ value: T, to url: URL) throws {
+        let encoder = JSONEncoder()
+        encoder.outputFormatting = [.sortedKeys, .prettyPrinted]
+        encoder.dateEncodingStrategy = .iso8601
+        let data: Data
+        do {
+            data = try encoder.encode(value)
+        } catch {
+            throw ShotdeckError.spoolWriteFailed(
+                path: url.path, underlying: "JSON encoding failed: \(error.localizedDescription)")
+        }
+        try write(data, to: url)
+    }
+
+    /// Opens `url` (must be an existing directory) and fsyncs it. Used after any directory-
+    /// level `rename()` (moving/renaming a whole session directory) — the same durability
+    /// requirement as the internal directory-fsync inside `write(_:to:)`, exposed for callers
+    /// that rename directories themselves (SpoolStore).
+    public static func fsyncDirectory(at url: URL) throws {
+        let fd = open(url.path, O_RDONLY | O_DIRECTORY)
+        guard fd >= 0 else {
+            throw ShotdeckError.spoolWriteFailed(
+                path: url.path,
+                underlying: "could not open directory for fsync: \(String(cString: strerror(errno)))")
+        }
+        let result = fsync(fd)
+        close(fd)
+        if result != 0 {
+            throw ShotdeckError.spoolWriteFailed(
+                path: url.path,
+                underlying: "directory fsync failed: \(String(cString: strerror(errno)))")
+        }
+    }
+}

Sources/ShotdeckCore/Support/DubaiTime.swift

@@ -0,0 +1,40 @@
+import Foundation
+
+public enum DubaiTime {
+    private static let stampFormatter = LockedDateFormatter(dateFormat: "d MMM yyyy, HH:mm 'Dubai'")
+    private static let fileStampFormatter = LockedDateFormatter(dateFormat: "yyyyMMdd-HHmmss")
+
+    public static func stamp(_ date: Date) -> String {
+        stampFormatter.string(from: date)
+    }
+
+    public static func fileStamp(_ date: Date) -> String {
+        fileStampFormatter.string(from: date)
+    }
+}
+
+/// DateFormatter is not Sendable. This holder is the only shared mutable state
+/// around a formatter: every read is serialized by the lock, so concurrent
+/// calls (one per PDF page) cannot race.
+private final class LockedDateFormatter: @unchecked Sendable {
+    private let lock = NSLock()
+    private let formatter: DateFormatter
+
+    init(dateFormat: String) {
+        let formatter = DateFormatter()
+        formatter.calendar = Calendar(identifier: .gregorian)
+        formatter.locale = Locale(identifier: "en_GB")
+        guard let dubai = TimeZone(identifier: "Asia/Dubai") else {
+            preconditionFailure("The Asia/Dubai time zone is missing from this system.")
+        }
+        formatter.timeZone = dubai
+        formatter.dateFormat = dateFormat
+        self.formatter = formatter
+    }
+
+    func string(from date: Date) -> String {
+        lock.lock()
+        defer { lock.unlock() }
+        return formatter.string(from: date)
+    }
+}

Sources/ShotdeckCore/Support/FolderSettings.swift

@@ -0,0 +1,111 @@
+import Foundation
+
+/// User-configurable overrides for the outbox (PDF send destination) and watch folder
+/// (AirDrop return), backed by UserDefaults. Shotdeck is NOT App-Sandboxed (no
+/// `com.apple.security.app-sandbox` entitlement in this build — it is a plain, unsandboxed
+/// SwiftPM executable). Security-scoped bookmarks exist to let a SANDBOXED app retain access
+/// to a user-picked file/folder outside its container across relaunches; an unsandboxed
+/// process already has the invoking user's own filesystem permissions on every launch, so a
+/// plain absolute path stored in UserDefaults is sufficient — including for a mounted network
+/// share, which resolves by path the same as any local folder for as long as it is mounted.
+public enum FolderSettings {
+    public static let outboxDefaultsKey = "ai.flowmaster.shotdeck.outbox"
+    public static let watchFolderDefaultsKey = "ai.flowmaster.shotdeck.watchFolder"
+
+    /// Raw stored path (or nil if never set / cleared). For display in Settings — does NOT
+    /// validate that the path still exists.
+    public static func storedOutboxPath(defaults: UserDefaults = .standard) -> String? {
+        defaults.string(forKey: outboxDefaultsKey)
+    }
+
+    public static func storedWatchFolderPath(defaults: UserDefaults = .standard) -> String? {
+        defaults.string(forKey: watchFolderDefaultsKey)
+    }
+
+    /// Persists a user-chosen folder as its absolute POSIX path.
+    public static func setOutbox(_ url: URL, defaults: UserDefaults = .standard) {
+        defaults.set(url.path, forKey: outboxDefaultsKey)
+    }
+
+    public static func setWatchFolder(_ url: URL, defaults: UserDefaults = .standard) {
+        defaults.set(url.path, forKey: watchFolderDefaultsKey)
+    }
+
+    /// Removes the override; resolve() falls back to the default again.
+    public static func resetOutbox(defaults: UserDefaults = .standard) {
+        defaults.removeObject(forKey: outboxDefaultsKey)
+    }
+
+    public static func resetWatchFolder(defaults: UserDefaults = .standard) {
+        defaults.removeObject(forKey: watchFolderDefaultsKey)
+    }
+
+    /// Resolves both folders. A stored override wins only if it is set AND the directory it
+    /// names still exists; otherwise falls back to the default (Desktop / Downloads). Never
+    /// throws — a missing/bad override is logged via `Log.ui` and silently replaced.
+    public static func resolve(
+        defaults: UserDefaults = .standard,
+        fileManager: FileManager = .default
+    ) -> (outbox: URL, watch: URL) {
+        let outbox = resolveOne(
+            storedPath: storedOutboxPath(defaults: defaults),
+            fallback: defaultOutbox(fileManager: fileManager),
+            label: "outbox", fileManager: fileManager)
+        let watch = resolveOne(
+            storedPath: storedWatchFolderPath(defaults: defaults),
+            fallback: defaultWatchFolder(fileManager: fileManager),
+            label: "watch", fileManager: fileManager)
+        return (outbox, watch)
+    }
+
+    /// Builds an `AppSupportPaths` using `root` (defaults to the standard
+    /// `~/Library/Application Support/Shotdeck`, computed the same way
+    /// `AppSupportPaths.standard()` does, when `root` is nil) plus whatever `resolve()`
+    /// returns for outbox/watch. This is the ONLY place that combines FolderSettings with
+    /// AppSupportPaths — call this everywhere in the app instead of `AppSupportPaths.standard()`.
+    /// `root` is exposed purely so tests can point it at a temporary directory instead of the
+    /// user's real Application Support folder.
+    public static func resolvedAppSupportPaths(
+        root: URL? = nil,
+        defaults: UserDefaults = .standard,
+        fileManager: FileManager = .default
+    ) throws -> AppSupportPaths {
+        let resolvedRoot: URL
+        if let root {
+            resolvedRoot = root
+        } else {
+            let appSupportParent = try fileManager.url(
+                for: .applicationSupportDirectory, in: .userDomainMask,
+                appropriateFor: nil, create: true)
+            resolvedRoot = appSupportParent.appendingPathComponent("Shotdeck", isDirectory: true)
+        }
+        let folders = resolve(defaults: defaults, fileManager: fileManager)
+        return try AppSupportPaths(root: resolvedRoot, outbox: folders.outbox, watchFolder: folders.watch)
+    }
+
+    private static func defaultOutbox(fileManager: FileManager) -> URL {
+        fileManager.urls(for: .desktopDirectory, in: .userDomainMask).first
+            ?? fileManager.homeDirectoryForCurrentUser.appendingPathComponent("Desktop", isDirectory: true)
+    }
+
+    private static func defaultWatchFolder(fileManager: FileManager) -> URL {
+        fileManager.urls(for: .downloadsDirectory, in: .userDomainMask).first
+            ?? fileManager.homeDirectoryForCurrentUser.appendingPathComponent("Downloads", isDirectory: true)
+    }
+
+    private static func resolveOne(
+        storedPath: String?,
+        fallback: URL,
+        label: String,
+        fileManager: FileManager
+    ) -> URL {
+        guard let storedPath else { return fallback }
+        var isDirectory: ObjCBool = false
+        let exists = fileManager.fileExists(atPath: storedPath, isDirectory: &isDirectory)
+        guard exists, isDirectory.boolValue else {
+            Log.ui.warning("Configured \(label, privacy: .public) folder \(storedPath, privacy: .public) no longer exists; falling back to the default.")
+            return fallback
+        }
+        return URL(fileURLWithPath: storedPath, isDirectory: true)
+    }
+}

Sources/ShotdeckCore/Support/Log.swift

@@ -0,0 +1,9 @@
+import os
+
+public enum Log {
+    public static let spool = Logger(subsystem: "ai.flowmaster.shotdeck", category: "spool")
+    public static let pdf = Logger(subsystem: "ai.flowmaster.shotdeck", category: "pdf")
+    public static let capture = Logger(subsystem: "ai.flowmaster.shotdeck", category: "capture")
+    public static let returns = Logger(subsystem: "ai.flowmaster.shotdeck", category: "returns")
+    public static let ui = Logger(subsystem: "ai.flowmaster.shotdeck", category: "ui")
+}

Tests/ShotdeckCoreTests/AnnotationInspectorTests.swift

@@ -0,0 +1,412 @@
+import AppKit
+import Foundation
+import PDFKit
+import Testing
+import ShotdeckCore
+
+private let pageBounds = CGRect(x: 0, y: 0, width: 600, height: 800)
+
+private func makeAnnotation(
+    _ subtype: PDFAnnotationSubtype,
+    bounds: CGRect = CGRect(x: 100, y: 100, width: 80, height: 40),
+    contents: String? = nil
+) -> PDFAnnotation {
+    let annotation = PDFAnnotation(
+        bounds: bounds,
+        forType: subtype,
+        withProperties: nil
+    )
+    annotation.contents = contents
+    return annotation
+}
+
+private func makePDF(
+    at url: URL,
+    pageCount: Int,
+    creator: String? = "Shotdeck",
+    subject: String? = nil,
+    annotations: [(page: Int, annotation: PDFAnnotation)] = []
+) throws {
+    let document = PDFDocument()
+    for index in 0..<pageCount {
+        let page = PDFPage()
+        page.setBounds(pageBounds, for: .mediaBox)
+        document.insert(page, at: index)
+    }
+
+    var attributes = [PDFDocumentAttribute: Any]()
+    if let creator { attributes[.creatorAttribute] = creator }
+    if let subject { attributes[.subjectAttribute] = subject }
+    document.documentAttributes = attributes
+
+    for item in annotations {
+        guard let page = document.page(at: item.page) else {
+            throw NSError(domain: "WP5Test", code: 1)
+        }
+        page.addAnnotation(item.annotation)
+    }
+
+    guard document.write(to: url) else {
+        throw NSError(domain: "WP5Test", code: 2)
+    }
+}
+
+private func makeCasePaths() throws -> (paths: AppSupportPaths, cleanup: URL) {
+    let cleanup = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-wp5a-\(UUID().uuidString)", isDirectory: true)
+    let paths = try AppSupportPaths(
+        root: cleanup.appendingPathComponent("root", isDirectory: true),
+        outbox: cleanup.appendingPathComponent("outbox", isDirectory: true),
+        watchFolder: cleanup.appendingPathComponent("watch", isDirectory: true)
+    )
+    return (paths, cleanup)
+}
+
+@Test("I-1 Untouched PDF is clean")
+func i1_untouchedPDFIsClean() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134200.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 3,
+        creator: "Shotdeck",
+        subject: "11111111-1111-1111-1111-111111111111"
+    )
+
+    var calendar = Calendar(identifier: .gregorian)
+    calendar.timeZone = try #require(TimeZone(identifier: "Asia/Dubai"))
+    let firstMTime = try #require(calendar.date(from: DateComponents(
+        year: 2026, month: 8, day: 30, hour: 13, minute: 42, second: 0
+    )))
+    let secondMTime = try #require(calendar.date(from: DateComponents(
+        year: 2026, month: 8, day: 30, hour: 13, minute: 43, second: 0
+    )))
+    try FileManager.default.setAttributes([.modificationDate: firstMTime], ofItemAtPath: pdfURL.path)
+    try FileManager.default.setAttributes([.modificationDate: secondMTime], ofItemAtPath: pdfURL.path)
+
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.fileURL == pdfURL)
+    #expect(inspected.sessionID == UUID(uuidString: "11111111-1111-1111-1111-111111111111"))
+    #expect(inspected.pageCount == 3)
+    #expect(inspected.annotatedPages == [])
+    #expect(inspected.isCommented == false)
+
+    let ledger = try ReturnLedger(paths: paths)
+    try await ledger.record(inspected)
+    let all = try await ledger.all()
+    #expect(all.count == 1)
+    #expect(all[0].fileURL == pdfURL)
+    #expect(try await ledger.commented() == [])
+    let clipboardError = try await #require(throws: ShotdeckError.self) {
+        try await ledger.clipboardText()
+    }
+    guard case .noCommentedReturns = clipboardError else {
+        Issue.record("expected noCommentedReturns, got \(clipboardError)")
+        return
+    }
+}
+
+@Test("I-2 Ink is a mark")
+func i2_inkIsAMark() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134201.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 3,
+        annotations: [(page: 1, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 120, y: 240, width: 140, height: 60)
+        ))]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.pageCount == 3)
+    #expect(inspected.annotatedPages == [2])
+    #expect(inspected.isCommented == true)
+}
+
+@Test("I-3 Highlight is a mark")
+func i3_highlightIsAMark() throws {
+    try expectSinglePageMark(
+        .highlight,
+        bounds: CGRect(x: 80, y: 500, width: 300, height: 24),
+        fileName: "Shotdeck-20260830-134202.pdf"
+    )
+}
+
+@Test("I-4 Underline is a mark")
+func i4_underlineIsAMark() throws {
+    try expectSinglePageMark(
+        .underline,
+        bounds: CGRect(x: 90, y: 460, width: 280, height: 18),
+        fileName: "Shotdeck-20260830-134203.pdf"
+    )
+}
+
+@Test("I-5 Strike-out is a mark")
+func i5_strikeOutIsAMark() throws {
+    try expectSinglePageMark(
+        .strikeOut,
+        bounds: CGRect(x: 90, y: 430, width: 280, height: 18),
+        fileName: "Shotdeck-20260830-134204.pdf"
+    )
+}
+
+@Test("I-6 Squiggly is a mark")
+func i6_squigglyIsAMark() throws {
+    try expectSinglePageMark(
+        PDFAnnotationSubtype(rawValue: "/Squiggly"),
+        bounds: CGRect(x: 90, y: 400, width: 280, height: 18),
+        fileName: "Shotdeck-20260830-134205.pdf"
+    )
+}
+
+@Test("I-7 Free-text is a mark")
+func i7_freeTextIsAMark() throws {
+    try expectSinglePageMark(
+        .freeText,
+        bounds: CGRect(x: 140, y: 300, width: 220, height: 80),
+        contents: "Typed review note",
+        fileName: "Shotdeck-20260830-134206.pdf"
+    )
+}
+
+@Test("I-8 Square is a mark")
+func i8_squareIsAMark() throws {
+    try expectSinglePageMark(
+        .square,
+        bounds: CGRect(x: 160, y: 250, width: 100, height: 100),
+        fileName: "Shotdeck-20260830-134207.pdf"
+    )
+}
+
+@Test("I-9 Circle is a mark")
+func i9_circleIsAMark() throws {
+    try expectSinglePageMark(
+        .circle,
+        bounds: CGRect(x: 280, y: 250, width: 100, height: 100),
+        fileName: "Shotdeck-20260830-134208.pdf"
+    )
+}
+
+@Test("I-10 Line is a mark")
+func i10_lineIsAMark() throws {
+    try expectSinglePageMark(
+        .line,
+        bounds: CGRect(x: 100, y: 180, width: 320, height: 8),
+        fileName: "Shotdeck-20260830-134209.pdf"
+    )
+}
+
+@Test("I-11 Stamp is a mark")
+func i11_stampIsAMark() throws {
+    try expectSinglePageMark(
+        .stamp,
+        bounds: CGRect(x: 180, y: 500, width: 120, height: 60),
+        contents: "Approved",
+        fileName: "Shotdeck-20260830-134210.pdf"
+    )
+}
+
+@Test("I-12 Sticky text is a mark")
+func i12_stickyTextIsAMark() throws {
+    try expectSinglePageMark(
+        .text,
+        bounds: CGRect(x: 420, y: 620, width: 28, height: 28),
+        contents: "Look here",
+        fileName: "Shotdeck-20260830-134211.pdf"
+    )
+}
+
+@Test("I-13 Link alone is not a mark")
+func i13_linkAloneIsNotAMark() throws {
+    try expectSinglePageIgnored(
+        .link,
+        bounds: CGRect(x: 80, y: 700, width: 160, height: 20),
+        fileName: "Shotdeck-20260830-134212.pdf"
+    )
+}
+
+@Test("I-14 Popup alone is not a mark")
+func i14_popupAloneIsNotAMark() throws {
+    try expectSinglePageIgnored(
+        .popup,
+        bounds: CGRect(x: 450, y: 600, width: 100, height: 60),
+        fileName: "Shotdeck-20260830-134213.pdf"
+    )
+}
+
+@Test("I-15 Widget alone is not a mark")
+func i15_widgetAloneIsNotAMark() throws {
+    try expectSinglePageIgnored(
+        .widget,
+        bounds: CGRect(x: 100, y: 100, width: 140, height: 32),
+        fileName: "Shotdeck-20260830-134214.pdf"
+    )
+}
+
+@Test("I-16 Zero-area ink is not a mark")
+func i16_zeroAreaInkIsNotAMark() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134215.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        annotations: [(page: 0, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 240, y: 240, width: 0, height: 0)
+        ))]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.annotatedPages == [])
+    #expect(inspected.isCommented == false)
+}
+
+@Test("I-17 Ignored objects plus one real mark count once")
+func i17_ignoredObjectsPlusOneRealMarkCountOnce() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134216.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 3,
+        annotations: [
+            (page: 1, annotation: makeAnnotation(.link, bounds: CGRect(x: 20, y: 20, width: 40, height: 20))),
+            (page: 1, annotation: makeAnnotation(.popup, bounds: CGRect(x: 70, y: 20, width: 40, height: 20))),
+            (page: 1, annotation: makeAnnotation(.widget, bounds: CGRect(x: 120, y: 20, width: 40, height: 20))),
+            (page: 1, annotation: makeAnnotation(.ink, bounds: CGRect(x: 200, y: 200, width: 120, height: 50))),
+        ]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.pageCount == 3)
+    #expect(inspected.annotatedPages == [2])
+    #expect(inspected.isCommented == true)
+}
+
+@Test("I-18 Page numbers are 1-based and ascending")
+func i18_pageNumbersAre1BasedAndAscending() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134217.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 3,
+        annotations: [
+            (page: 0, annotation: makeAnnotation(.circle, bounds: CGRect(x: 260, y: 200, width: 70, height: 70))),
+            (page: 1, annotation: makeAnnotation(.link, bounds: CGRect(x: 80, y: 700, width: 160, height: 20))),
+            (page: 2, annotation: makeAnnotation(.ink, bounds: CGRect(x: 100, y: 100, width: 90, height: 40))),
+        ]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.pageCount == 3)
+    #expect(inspected.annotatedPages == [1, 3])
+    #expect(inspected.isCommented == true)
+}
+
+@Test("I-19 Session UUID recovery and invalid-subject tolerance")
+func i19_sessionUUIDRecoveryAndInvalidSubjectTolerance() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let validURL = paths.watchFolder.appendingPathComponent("valid-subject.pdf")
+    let invalidURL = paths.watchFolder.appendingPathComponent("invalid-subject.pdf")
+    let missingURL = paths.watchFolder.appendingPathComponent("missing-subject.pdf")
+
+    try makePDF(
+        at: validURL,
+        pageCount: 1,
+        creator: "Shotdeck",
+        subject: "22222222-2222-2222-2222-222222222222"
+    )
+    try makePDF(
+        at: invalidURL,
+        pageCount: 1,
+        creator: "Shotdeck",
+        subject: "not-a-uuid"
+    )
+    try makePDF(
+        at: missingURL,
+        pageCount: 1,
+        creator: "Shotdeck",
+        subject: nil
+    )
+
+    let valid = try AnnotationInspector.inspect(fileURL: validURL)
+    #expect(valid.sessionID == UUID(uuidString: "22222222-2222-2222-2222-222222222222"))
+    #expect(valid.pageCount == 1)
+    #expect(valid.annotatedPages == [])
+    #expect(valid.isCommented == false)
+
+    let invalid = try AnnotationInspector.inspect(fileURL: invalidURL)
+    #expect(invalid.sessionID == nil)
+    #expect(invalid.annotatedPages == [])
+    #expect(invalid.isCommented == false)
+
+    let missing = try AnnotationInspector.inspect(fileURL: missingURL)
+    #expect(missing.sessionID == nil)
+    #expect(missing.annotatedPages == [])
+    #expect(missing.isCommented == false)
+}
+
+@Test("I-19b Present non-Shotdeck creator beats a matching filename")
+func i19b_presentNonShotdeckCreatorBeatsMatchingFilename() throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134218.pdf")
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        creator: "Preview",
+        annotations: [(page: 0, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 100, y: 100, width: 120, height: 50)
+        ))]
+    )
+    let reopened = try #require(PDFDocument(url: pdfURL))
+    #expect(AnnotationInspector.isShotdeckDocument(reopened) == false)
+}
+
+private func expectSinglePageMark(
+    _ subtype: PDFAnnotationSubtype,
+    bounds: CGRect,
+    contents: String? = nil,
+    fileName: String
+) throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent(fileName)
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        annotations: [(page: 0, annotation: makeAnnotation(subtype, bounds: bounds, contents: contents))]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.pageCount == 1)
+    #expect(inspected.annotatedPages == [1])
+    #expect(inspected.isCommented == true)
+}
+
+private func expectSinglePageIgnored(
+    _ subtype: PDFAnnotationSubtype,
+    bounds: CGRect,
+    fileName: String
+) throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let pdfURL = paths.watchFolder.appendingPathComponent(fileName)
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        annotations: [(page: 0, annotation: makeAnnotation(subtype, bounds: bounds))]
+    )
+    let inspected = try AnnotationInspector.inspect(fileURL: pdfURL)
+    #expect(inspected.annotatedPages == [])
+    #expect(inspected.isCommented == false)
+}

Tests/ShotdeckCoreTests/AppSupportPathsTests.swift

@@ -0,0 +1,75 @@
+import Foundation
+import Testing
+import ShotdeckCore
+
+@Test
+func appSupportPathsCreatesEveryNamedDirectory() throws {
+    let temporaryRoot = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-paths-\(UUID().uuidString)", isDirectory: true)
+    defer { try? FileManager.default.removeItem(at: temporaryRoot) }
+
+    let root = temporaryRoot.appendingPathComponent("root", isDirectory: true)
+    let outbox = temporaryRoot.appendingPathComponent("outbox", isDirectory: true)
+    let watchFolder = temporaryRoot.appendingPathComponent("watch", isDirectory: true)
+
+    let paths = try AppSupportPaths(root: root, outbox: outbox, watchFolder: watchFolder)
+
+    #expect(directoryExists(paths.root))
+    #expect(directoryExists(paths.spool))
+    #expect(directoryExists(paths.archive))
+    #expect(directoryExists(paths.outbox))
+    #expect(directoryExists(paths.watchFolder))
+
+    #expect(paths.spool.path == root.appendingPathComponent("spool", isDirectory: true).path)
+    #expect(paths.archive.path == root.appendingPathComponent("archive", isDirectory: true).path)
+}
+
+@Test
+func sessionAndArchiveDirectoriesAreDistinctUnderTheRightParents() throws {
+    let temporaryRoot = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-dirs-\(UUID().uuidString)", isDirectory: true)
+    defer { try? FileManager.default.removeItem(at: temporaryRoot) }
+
+    let paths = try AppSupportPaths(
+        root: temporaryRoot.appendingPathComponent("root", isDirectory: true),
+        outbox: temporaryRoot.appendingPathComponent("outbox", isDirectory: true),
+        watchFolder: temporaryRoot.appendingPathComponent("watch", isDirectory: true)
+    )
+
+    let sessionID = UUID()
+    let sessionDirectory = paths.sessionDirectory(sessionID)
+    let archiveDirectory = paths.archiveDirectory(sessionID)
+
+    #expect(sessionDirectory.path != archiveDirectory.path)
+    #expect(sessionDirectory.deletingLastPathComponent().path == paths.spool.path)
+    #expect(archiveDirectory.deletingLastPathComponent().path == paths.archive.path)
+    #expect(sessionDirectory.lastPathComponent == sessionID.uuidString)
+    #expect(archiveDirectory.lastPathComponent == sessionID.uuidString)
+}
+
+@Test
+func dubaiTimeStampRendersAKnownInstantInAsiaDubai() throws {
+    var calendar = Calendar(identifier: .gregorian)
+    let dubai = try #require(TimeZone(identifier: "Asia/Dubai"))
+    calendar.timeZone = dubai
+
+    let date = try #require(
+        calendar.date(from: DateComponents(
+            year: 2026,
+            month: 8,
+            day: 30,
+            hour: 13,
+            minute: 42,
+            second: 5
+        ))
+    )
+
+    #expect(DubaiTime.stamp(date) == "30 Aug 2026, 13:42 Dubai")
+    #expect(DubaiTime.fileStamp(date) == "20260830-134205")
+}
+
+private func directoryExists(_ url: URL) -> Bool {
+    var isDirectory: ObjCBool = false
+    let exists = FileManager.default.fileExists(atPath: url.path, isDirectory: &isDirectory)
+    return exists && isDirectory.boolValue
+}

Tests/ShotdeckCoreTests/AtomicFileTests.swift

@@ -0,0 +1,178 @@
+import Foundation
+import Testing
+import ShotdeckCore
+
+@Test
+func atomicWriteProducesByteIdenticalFileAndLeavesNoTmp() throws {
+    let directory = try makeTemporaryDirectory(prefix: "shotdeck-atomic-write")
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let url = directory.appendingPathComponent("payload.bin")
+    let data = Data("shotdeck-durable-bytes".utf8)
+
+    try AtomicFile.write(data, to: url)
+
+    let onDisk = try Data(contentsOf: url)
+    #expect(onDisk == data)
+    #expect(!FileManager.default.fileExists(atPath: url.path + ".tmp"))
+}
+
+@Test
+func atomicWriteToTheSameURLTwiceKeepsTheSecondPayload() throws {
+    let directory = try makeTemporaryDirectory(prefix: "shotdeck-atomic-rewrite")
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let url = directory.appendingPathComponent("payload.bin")
+    let first = Data("first-pass".utf8)
+    let second = Data("second-pass-wins".utf8)
+
+    try AtomicFile.write(first, to: url)
+    try AtomicFile.write(second, to: url)
+
+    let onDisk = try Data(contentsOf: url)
+    #expect(onDisk == second)
+    #expect(!FileManager.default.fileExists(atPath: url.path + ".tmp"))
+}
+
+@Test
+func atomicWriteThrowsWhenParentDirectoryDoesNotExist() throws {
+    let missingParent = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-atomic-missing-\(UUID().uuidString)", isDirectory: true)
+    let url = missingParent.appendingPathComponent("payload.bin")
+    let data = Data("never-written".utf8)
+
+    let error = try #require(throws: ShotdeckError.self) {
+        try AtomicFile.write(data, to: url)
+    }
+    guard case .spoolWriteFailed(let path, _) = error else {
+        Issue.record("expected spoolWriteFailed, got \(error)")
+        return
+    }
+    #expect(path == url.path)
+    #expect(!FileManager.default.fileExists(atPath: url.path))
+}
+
+@Test
+func atomicWriteClearsAStaleTmpAndWritesTheNewPayload() throws {
+    let directory = try makeTemporaryDirectory(prefix: "shotdeck-atomic-stale-tmp")
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let url = directory.appendingPathComponent("payload.bin")
+    let tmpURL = directory.appendingPathComponent(url.lastPathComponent + ".tmp")
+    let garbage = Data("stale-crash-garbage".utf8)
+    let newData = Data("recovered-payload".utf8)
+
+    try garbage.write(to: tmpURL)
+    #expect(FileManager.default.fileExists(atPath: tmpURL.path))
+
+    try AtomicFile.write(newData, to: url)
+
+    let onDisk = try Data(contentsOf: url)
+    #expect(onDisk == newData)
+    #expect(!FileManager.default.fileExists(atPath: tmpURL.path))
+}
+
+@Test
+func writeJSONSortsKeysPrettyPrintsAndEncodesDatesAsISO8601() throws {
+    let directory = try makeTemporaryDirectory(prefix: "shotdeck-atomic-json-format")
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let url = directory.appendingPathComponent("session.json")
+    let date = try iso8601Date(year: 2026, month: 8, day: 30, hour: 9, minute: 42, second: 5)
+    let value = JSONProbe(zebra: "last", apple: 7, capturedAt: date)
+
+    try AtomicFile.writeJSON(value, to: url)
+
+    let raw = try Data(contentsOf: url)
+    let text = try #require(String(data: raw, encoding: .utf8))
+
+    let apple = try #require(text.range(of: "\"apple\""))
+    let capturedAt = try #require(text.range(of: "\"capturedAt\""))
+    let zebra = try #require(text.range(of: "\"zebra\""))
+    #expect(apple.lowerBound < capturedAt.lowerBound)
+    #expect(capturedAt.lowerBound < zebra.lowerBound)
+    #expect(text.contains("\n"))
+    #expect(text.contains("  \"apple\""))
+    #expect(text.contains("2026-08-30T09:42:05Z"))
+    #expect(!text.contains("\(date.timeIntervalSinceReferenceDate)"))
+    #expect(!FileManager.default.fileExists(atPath: url.path + ".tmp"))
+}
+
+@Test
+func writeJSONRoundTripsThroughISO8601Decoder() throws {
+    let directory = try makeTemporaryDirectory(prefix: "shotdeck-atomic-json-roundtrip")
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let url = directory.appendingPathComponent("session.json")
+    let date = try iso8601Date(year: 2026, month: 8, day: 31, hour: 13, minute: 5, second: 9)
+    let original = JSONProbe(zebra: "keep", apple: 42, capturedAt: date)
+
+    try AtomicFile.writeJSON(original, to: url)
+
+    let decoder = JSONDecoder()
+    decoder.dateDecodingStrategy = .iso8601
+    let decoded = try decoder.decode(JSONProbe.self, from: Data(contentsOf: url))
+    #expect(decoded == original)
+}
+
+@Test
+func fsyncDirectorySucceedsOnADirectoryAndThrowsOnMissingOrFilePaths() throws {
+    let directory = try makeTemporaryDirectory(prefix: "shotdeck-atomic-fsync-dir")
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    try AtomicFile.fsyncDirectory(at: directory)
+
+    let missing = directory.appendingPathComponent("does-not-exist", isDirectory: true)
+    let missingError = try #require(throws: ShotdeckError.self) {
+        try AtomicFile.fsyncDirectory(at: missing)
+    }
+    guard case .spoolWriteFailed = missingError else {
+        Issue.record("expected spoolWriteFailed for a missing path, got \(missingError)")
+        return
+    }
+
+    let fileURL = directory.appendingPathComponent("not-a-directory.bin")
+    try AtomicFile.write(Data("file".utf8), to: fileURL)
+    let fileError = try #require(throws: ShotdeckError.self) {
+        try AtomicFile.fsyncDirectory(at: fileURL)
+    }
+    guard case .spoolWriteFailed = fileError else {
+        Issue.record("expected spoolWriteFailed for a file path, got \(fileError)")
+        return
+    }
+}
+
+private struct JSONProbe: Codable, Equatable {
+    var zebra: String
+    var apple: Int
+    var capturedAt: Date
+}
+
+private func makeTemporaryDirectory(prefix: String) throws -> URL {
+    let url = FileManager.default.temporaryDirectory
+        .appendingPathComponent("\(prefix)-\(UUID().uuidString)", isDirectory: true)
+    try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true)
+    return url
+}
+
+private func iso8601Date(
+    year: Int,
+    month: Int,
+    day: Int,
+    hour: Int,
+    minute: Int,
+    second: Int
+) throws -> Date {
+    var calendar = Calendar(identifier: .gregorian)
+    calendar.timeZone = try #require(TimeZone(secondsFromGMT: 0))
+    return try #require(
+        calendar.date(from: DateComponents(
+            year: year,
+            month: month,
+            day: day,
+            hour: hour,
+            minute: minute,
+            second: second
+        ))
+    )
+}

Tests/ShotdeckCoreTests/CaptureRegionTests.swift

@@ -0,0 +1,171 @@
+import Carbon.HIToolbox
+import Foundation
+import Testing
+@testable import ShotdeckCore
+
+@Test("GEO-1 primary-only 1080-tall screen, AppKit rect (100,100,400,300)")
+func geo1_primaryOnlyAppKitRectConvertsToExpectedCGRect() {
+    let region = CaptureRegion.fromAppKit(
+        rect: CGRect(x: 100, y: 100, width: 400, height: 300),
+        displayID: 1,
+        capturedScale: 2,
+        primaryHeight: 1080
+    )
+    #expect(region.rect == CGRect(x: 100, y: 680, width: 400, height: 300))
+}
+
+@Test("GEO-2 rect flush to AppKit bottom (y=0), h=300, primaryHeight=1080")
+func geo2_flushToAppKitBottomYieldsCGY780() {
+    let region = CaptureRegion.fromAppKit(
+        rect: CGRect(x: 50, y: 0, width: 200, height: 300),
+        displayID: 1,
+        capturedScale: 1,
+        primaryHeight: 1080
+    )
+    #expect(region.rect.origin.y == 780)
+}
+
+@Test("GEO-3 rect flush to AppKit top (y+h=primaryHeight), primaryHeight=1080, h=300")
+func geo3_flushToAppKitTopYieldsCGY0() {
+    let region = CaptureRegion.fromAppKit(
+        rect: CGRect(x: 50, y: 780, width: 200, height: 300),
+        displayID: 1,
+        capturedScale: 1,
+        primaryHeight: 1080
+    )
+    #expect(region.rect.origin.y == 0)
+}
+
+@Test("GEO-4 round-trip AppKit→CG via injectable overload, then invert recovers original")
+func geo4_invertRecoverOriginalAppKitRect() {
+    let original = CGRect(x: 100, y: 100, width: 400, height: 300)
+    let primaryHeight: CGFloat = 1080
+    let region = CaptureRegion.fromAppKit(
+        rect: original,
+        displayID: 1,
+        capturedScale: 2,
+        primaryHeight: primaryHeight
+    )
+    let appKitY = primaryHeight - region.rect.origin.y - region.rect.height
+    let recovered = CGRect(
+        x: region.rect.origin.x,
+        y: appKitY,
+        width: region.rect.width,
+        height: region.rect.height
+    )
+    #expect(recovered == original)
+}
+
+@Test("GEO-5 isStillValid for displayID 999_999 is false and does not trap")
+func geo5_unknownDisplayIsNotStillValid() {
+    let region = CaptureRegion(
+        displayID: 999_999,
+        rect: CGRect(x: 0, y: 0, width: 100, height: 100),
+        capturedScale: 1
+    )
+    #expect(region.isStillValid == false)
+}
+
+@Test("GEO-6 CaptureRegion JSONEncoder→JSONDecoder round-trip equals original")
+func geo6_codableRoundTripEqualsOriginal() throws {
+    let original = CaptureRegion(
+        displayID: 42,
+        rect: CGRect(x: 10, y: 20, width: 300, height: 400),
+        capturedScale: 2
+    )
+    let data = try JSONEncoder().encode(original)
+    let decoded = try JSONDecoder().decode(CaptureRegion.self, from: data)
+    #expect(decoded == original)
+}
+
+@Test("GEO-7 secondary screen negative x: AppKit (−1800,200,500,400) → CG (−1800,480,500,400)")
+func geo7_secondaryNegativeXLeavesXUnchanged() {
+    // Secondary AppKit frame (−1920, 0, 1920, 1080); primaryHeight=1080.
+    let region = CaptureRegion.fromAppKit(
+        rect: CGRect(x: -1800, y: 200, width: 500, height: 400),
+        displayID: 2,
+        capturedScale: 1,
+        primaryHeight: 1080
+    )
+    #expect(region.rect == CGRect(x: -1800, y: 480, width: 500, height: 400))
+}
+
+@Test("GEO-8 secondary screen stacked above primary: AppKit (300,1300,600,350) → CG (300,−570,600,350)")
+func geo8_secondaryPositiveYProducesNegativeCGY() {
+    // Secondary AppKit frame (0, 1080, 1920, 1080); primaryHeight=1080.
+    let region = CaptureRegion.fromAppKit(
+        rect: CGRect(x: 300, y: 1300, width: 600, height: 350),
+        displayID: 2,
+        capturedScale: 1,
+        primaryHeight: 1080
+    )
+    #expect(region.rect == CGRect(x: 300, y: -570, width: 600, height: 350))
+}
+
+/// Carbon registrations are process-wide, so these cases must not run in parallel.
+@Suite(.serialized)
+@MainActor
+struct HotkeyCenterCarbonTests {
+    /// kVK_ANSI_2. The app registers this combo once (WP-4a); tests only exercise the registrar.
+    private let captureKeyCode: UInt32 = 19
+    private let captureModifiers = UInt32(optionKey) | UInt32(shiftKey)
+
+    @Test("HK-1 register id a with Option-Shift-2 returns true")
+    func hk1_registerReturnsTrue() {
+        let center = HotkeyCenter()
+        defer { center.unregisterAll() }
+        let ok = center.register(id: "a", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        if !ok {
+            Issue.record("HK-1: RegisterEventHotKey returned non-noErr inside swift test (no NSApplication). Carbon registration did not function headlessly.")
+            return
+        }
+        #expect(ok)
+    }
+
+    @Test("HK-2 register same combo under a different id returns false")
+    func hk2_duplicateComboRejected() {
+        let center = HotkeyCenter()
+        defer { center.unregisterAll() }
+        let first = center.register(id: "a", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        if !first {
+            Issue.record("HK-2: first RegisterEventHotKey failed inside swift test (no NSApplication); cannot evaluate duplicate-combo rejection.")
+            return
+        }
+        let second = center.register(id: "b", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        #expect(second == false)
+    }
+
+    @Test("HK-3 unregister frees the combination so a later register succeeds")
+    func hk3_unregisterFreesCombination() {
+        let center = HotkeyCenter()
+        defer { center.unregisterAll() }
+        let first = center.register(id: "a", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        if !first {
+            Issue.record("HK-3: first RegisterEventHotKey failed inside swift test (no NSApplication); cannot evaluate unregister.")
+            return
+        }
+        center.unregister(id: "a")
+        let again = center.register(id: "c", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        #expect(again)
+    }
+
+    @Test("HK-4 unregisterAll frees combinations so a later register succeeds")
+    func hk4_unregisterAllFreesCombinations() {
+        let center = HotkeyCenter()
+        defer { center.unregisterAll() }
+        let first = center.register(id: "a", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        let other = center.register(
+            id: "other",
+            keyCode: UInt32(kVK_ANSI_3),
+            modifiers: captureModifiers
+        ) {}
+        if !first {
+            Issue.record("HK-4: RegisterEventHotKey failed inside swift test (no NSApplication); cannot evaluate unregisterAll.")
+            return
+        }
+        _ = other
+        center.unregisterAll()
+        let again = center.register(id: "c", keyCode: captureKeyCode, modifiers: captureModifiers) {}
+        #expect(again)
+    }
+}

Tests/ShotdeckCoreTests/FolderSettingsTests.swift

@@ -0,0 +1,168 @@
+import Foundation
+import Testing
+import ShotdeckCore
+
+@Test
+func resolveWithoutStoredKeysReturnsDesktopAndDownloads() throws {
+    let suite = try makeDefaultsSuite()
+    defer { tearDown(suite) }
+
+    let resolved = FolderSettings.resolve(defaults: suite.defaults)
+    let expectedOutbox = try #require(
+        FileManager.default.urls(for: .desktopDirectory, in: .userDomainMask).first
+    )
+    let expectedWatch = try #require(
+        FileManager.default.urls(for: .downloadsDirectory, in: .userDomainMask).first
+    )
+
+    #expect(resolved.outbox.path == expectedOutbox.path)
+    #expect(resolved.watch.path == expectedWatch.path)
+}
+
+@Test
+func setOutboxToAnExistingDirectoryIsReturnedByResolve() throws {
+    let suite = try makeDefaultsSuite()
+    defer { tearDown(suite) }
+    let outbox = try makeTemporaryDirectory(prefix: "shotdeck-outbox-set")
+    defer { try? FileManager.default.removeItem(at: outbox) }
+
+    FolderSettings.setOutbox(outbox, defaults: suite.defaults)
+    let resolved = FolderSettings.resolve(defaults: suite.defaults)
+    let expectedWatch = try #require(
+        FileManager.default.urls(for: .downloadsDirectory, in: .userDomainMask).first
+    )
+
+    #expect(resolved.outbox.path == outbox.path)
+    #expect(resolved.watch.path == expectedWatch.path)
+    #expect(FolderSettings.storedOutboxPath(defaults: suite.defaults) == outbox.path)
+}
+
+@Test
+func resolveFallsBackWhenTheStoredOutboxDirectoryIsGone() throws {
+    let suite = try makeDefaultsSuite()
+    defer { tearDown(suite) }
+    let outbox = try makeTemporaryDirectory(prefix: "shotdeck-outbox-gone")
+
+    FolderSettings.setOutbox(outbox, defaults: suite.defaults)
+    try FileManager.default.removeItem(at: outbox)
+
+    let resolved = FolderSettings.resolve(defaults: suite.defaults)
+    let expectedOutbox = try #require(
+        FileManager.default.urls(for: .desktopDirectory, in: .userDomainMask).first
+    )
+    #expect(resolved.outbox.path == expectedOutbox.path)
+}
+
+@Test
+func setWatchFolderMirrorsOutboxOverrideAndFallbackIndependently() throws {
+    let suite = try makeDefaultsSuite()
+    defer { tearDown(suite) }
+    let watch = try makeTemporaryDirectory(prefix: "shotdeck-watch-set")
+    let expectedOutbox = try #require(
+        FileManager.default.urls(for: .desktopDirectory, in: .userDomainMask).first
+    )
+
+    FolderSettings.setWatchFolder(watch, defaults: suite.defaults)
+    let withOverride = FolderSettings.resolve(defaults: suite.defaults)
+    #expect(withOverride.watch.path == watch.path)
+    #expect(withOverride.outbox.path == expectedOutbox.path)
+
+    try FileManager.default.removeItem(at: watch)
+    let afterDelete = FolderSettings.resolve(defaults: suite.defaults)
+    let expectedWatch = try #require(
+        FileManager.default.urls(for: .downloadsDirectory, in: .userDomainMask).first
+    )
+    #expect(afterDelete.watch.path == expectedWatch.path)
+    #expect(afterDelete.outbox.path == expectedOutbox.path)
+}
+
+@Test
+func resetOutboxClearsTheOverride() throws {
+    let suite = try makeDefaultsSuite()
+    defer { tearDown(suite) }
+    let outbox = try makeTemporaryDirectory(prefix: "shotdeck-outbox-reset")
+    defer { try? FileManager.default.removeItem(at: outbox) }
+
+    FolderSettings.setOutbox(outbox, defaults: suite.defaults)
+    FolderSettings.resetOutbox(defaults: suite.defaults)
+
+    let resolved = FolderSettings.resolve(defaults: suite.defaults)
+    let expectedOutbox = try #require(
+        FileManager.default.urls(for: .desktopDirectory, in: .userDomainMask).first
+    )
+    #expect(resolved.outbox.path == expectedOutbox.path)
+    #expect(FolderSettings.storedOutboxPath(defaults: suite.defaults) == nil)
+}
+
+@Test
+func resolvedAppSupportPathsUsesTheOutboxOverrideAndCreatesSpoolArchive() throws {
+    let suite = try makeDefaultsSuite()
+    defer { tearDown(suite) }
+    let root = try makeTemporaryDirectory(prefix: "shotdeck-paths-root")
+    let outbox = try makeTemporaryDirectory(prefix: "shotdeck-paths-outbox")
+    defer {
+        try? FileManager.default.removeItem(at: root)
+        try? FileManager.default.removeItem(at: outbox)
+    }
+
+    FolderSettings.setOutbox(outbox, defaults: suite.defaults)
+    let paths = try FolderSettings.resolvedAppSupportPaths(root: root, defaults: suite.defaults)
+
+    #expect(paths.outbox.path == outbox.path)
+    #expect(directoryExists(paths.spool))
+    #expect(directoryExists(paths.archive))
+    #expect(paths.spool.deletingLastPathComponent().path == root.path)
+    #expect(paths.archive.deletingLastPathComponent().path == root.path)
+}
+
+@Test
+func userDefaultsSuitesDoNotLeakFolderOverrides() throws {
+    let suiteA = try makeDefaultsSuite()
+    let suiteB = try makeDefaultsSuite()
+    defer {
+        tearDown(suiteA)
+        tearDown(suiteB)
+    }
+    let outbox = try makeTemporaryDirectory(prefix: "shotdeck-suite-a-outbox")
+    defer { try? FileManager.default.removeItem(at: outbox) }
+
+    FolderSettings.setOutbox(outbox, defaults: suiteA.defaults)
+
+    let resolvedA = FolderSettings.resolve(defaults: suiteA.defaults)
+    let resolvedB = FolderSettings.resolve(defaults: suiteB.defaults)
+    let expectedOutbox = try #require(
+        FileManager.default.urls(for: .desktopDirectory, in: .userDomainMask).first
+    )
+
+    #expect(resolvedA.outbox.path == outbox.path)
+    #expect(resolvedB.outbox.path == expectedOutbox.path)
+}
+
+private struct DefaultsSuite {
+    let name: String
+    let defaults: UserDefaults
+}
+
+private func makeDefaultsSuite() throws -> DefaultsSuite {
+    let name = "shotdeck-test-\(UUID().uuidString)"
+    let defaults = try #require(UserDefaults(suiteName: name))
+    defaults.removePersistentDomain(forName: name)
+    return DefaultsSuite(name: name, defaults: defaults)
+}
+
+private func tearDown(_ suite: DefaultsSuite) {
+    suite.defaults.removePersistentDomain(forName: suite.name)
+}
+
+private func makeTemporaryDirectory(prefix: String) throws -> URL {
+    let url = FileManager.default.temporaryDirectory
+        .appendingPathComponent("\(prefix)-\(UUID().uuidString)", isDirectory: true)
+    try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true)
+    return url
+}
+
+private func directoryExists(_ url: URL) -> Bool {
+    var isDirectory: ObjCBool = false
+    let exists = FileManager.default.fileExists(atPath: url.path, isDirectory: &isDirectory)
+    return exists && isDirectory.boolValue
+}

Tests/ShotdeckCoreTests/PDFComposerTests.swift

@@ -0,0 +1,579 @@
+import CoreGraphics
+import Foundation
+import ImageIO
+import PDFKit
+import ShotdeckCore
+import Testing
+import UniformTypeIdentifiers
+
+enum TestFixtureError: Error { case cannotCreateBitmap, cannotCreatePNG, cannotFinalizePNG }
+
+func writeSolidPNG(
+    pixelWidth: Int,
+    pixelHeight: Int,
+    red: UInt8,
+    green: UInt8,
+    blue: UInt8,
+    to url: URL
+) throws {
+    let colorSpace = CGColorSpaceCreateDeviceRGB()
+    guard let context = CGContext(
+        data: nil,
+        width: pixelWidth,
+        height: pixelHeight,
+        bitsPerComponent: 8,
+        bytesPerRow: pixelWidth * 4,
+        space: colorSpace,
+        bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue
+    ) else { throw TestFixtureError.cannotCreateBitmap }
+    context.setFillColor(CGColor(
+        red: CGFloat(red) / 255,
+        green: CGFloat(green) / 255,
+        blue: CGFloat(blue) / 255,
+        alpha: 1
+    ))
+    context.fill(CGRect(x: 0, y: 0, width: pixelWidth, height: pixelHeight))
+    guard let image = context.makeImage(),
+          let destination = CGImageDestinationCreateWithURL(
+              url as CFURL,
+              UTType.png.identifier as CFString,
+              1,
+              nil
+          )
+    else { throw TestFixtureError.cannotCreatePNG }
+    CGImageDestinationAddImage(destination, image, nil)
+    guard CGImageDestinationFinalize(destination) else { throw TestFixtureError.cannotFinalizePNG }
+}
+
+private let fixtureDate = Date(timeIntervalSince1970: 1_777_482_180)
+
+private func makeCapture(
+    sequence: Int,
+    pixelWidth: Int,
+    pixelHeight: Int,
+    scale: CGFloat = 1,
+    capturedAt: Date = fixtureDate,
+    id: UUID = UUID(),
+    fileName: String? = nil
+) -> Capture {
+    Capture(
+        id: id,
+        sequence: sequence,
+        fileName: fileName ?? String(format: "%03d.png", sequence),
+        pixelWidth: pixelWidth,
+        pixelHeight: pixelHeight,
+        scale: scale,
+        capturedAt: capturedAt
+    )
+}
+
+private func makeSession(
+    captures: [Capture],
+    id: UUID = UUID(),
+    createdAt: Date = fixtureDate
+) -> CaptureSession {
+    CaptureSession(
+        id: id,
+        createdAt: createdAt,
+        state: .open,
+        captures: captures,
+        pdfFileName: nil
+    )
+}
+
+private func makeScratchDirectory() throws -> URL {
+    let url = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-pdf-\(UUID().uuidString)", isDirectory: true)
+    try FileManager.default.createDirectory(at: url, withIntermediateDirectories: true)
+    return url
+}
+
+private func writePNG(
+    for capture: Capture,
+    red: UInt8,
+    green: UInt8,
+    blue: UInt8,
+    in directory: URL
+) throws -> URL {
+    let url = directory.appendingPathComponent(capture.fileName)
+    try writeSolidPNG(
+        pixelWidth: capture.pixelWidth,
+        pixelHeight: capture.pixelHeight,
+        red: red,
+        green: green,
+        blue: blue,
+        to: url
+    )
+    return url
+}
+
+private func imageURLMap(_ urls: [UUID: URL]) -> (Capture) -> URL {
+    { capture in
+        urls[capture.id] ?? URL(fileURLWithPath: "/nonexistent/\(capture.id.uuidString).png")
+    }
+}
+
+private func openDocument(_ url: URL) throws -> PDFDocument {
+    let document = try #require(PDFDocument(url: url))
+    return document
+}
+
+private func pdftoppm(pdf: URL, prefix: URL) throws {
+    let process = Process()
+    process.executableURL = URL(fileURLWithPath: "/opt/homebrew/bin/pdftoppm")
+    process.arguments = ["-png", "-r", "110", pdf.path, prefix.path]
+    let err = Pipe()
+    process.standardError = err
+    try process.run()
+    process.waitUntilExit()
+    guard process.terminationStatus == 0 else {
+        let message = String(data: err.fileHandleForReading.readDataToEndOfFile(), encoding: .utf8) ?? ""
+        throw ShotdeckError.pdfCompositionFailed(reason: "pdftoppm failed: \(message)")
+    }
+}
+
+private struct RGBABitmap {
+    let width: Int
+    let height: Int
+    let bytesPerRow: Int
+    let data: Data
+
+    func pixel(x: Int, y: Int) -> (UInt8, UInt8, UInt8)? {
+        guard x >= 0, y >= 0, x < width, y < height else { return nil }
+        let offset = y * bytesPerRow + x * 4
+        guard offset + 2 < data.count else { return nil }
+        return (data[offset], data[offset + 1], data[offset + 2])
+    }
+
+    func containsNonWhite(x0: Int, y0: Int, x1: Int, y1: Int) -> Bool {
+        let xStart = max(0, x0)
+        let yStart = max(0, y0)
+        let xEnd = min(width, x1)
+        let yEnd = min(height, y1)
+        guard xStart < xEnd, yStart < yEnd else { return false }
+        for y in yStart..<yEnd {
+            for x in xStart..<xEnd {
+                if let (r, g, b) = pixel(x: x, y: y), r != 255 || g != 255 || b != 255 {
+                    return true
+                }
+            }
+        }
+        return false
+    }
+
+    static func loadPNG(at url: URL) throws -> RGBABitmap {
+        let colorSpace = CGColorSpaceCreateDeviceRGB()
+        let source = try #require(CGImageSourceCreateWithURL(url as CFURL, nil))
+        let image = try #require(CGImageSourceCreateImageAtIndex(source, 0, nil))
+        let width = image.width
+        let height = image.height
+        let bytesPerRow = width * 4
+        var data = Data(count: bytesPerRow * height)
+        try data.withUnsafeMutableBytes { raw in
+            guard let base = raw.baseAddress else {
+                throw TestFixtureError.cannotCreateBitmap
+            }
+            guard let context = CGContext(
+                data: base,
+                width: width,
+                height: height,
+                bitsPerComponent: 8,
+                bytesPerRow: bytesPerRow,
+                space: colorSpace,
+                bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue
+            ) else {
+                throw TestFixtureError.cannotCreateBitmap
+            }
+            context.interpolationQuality = .none
+            context.draw(image, in: CGRect(x: 0, y: 0, width: width, height: height))
+        }
+        return RGBABitmap(width: width, height: height, bytesPerRow: bytesPerRow, data: data)
+    }
+}
+
+private func pixelWindow(
+    for rect: CGRect,
+    pageHeightPt: CGFloat,
+    scale k: CGFloat
+) -> (x0: Int, y0: Int, x1: Int, y1: Int) {
+    let pixelX0 = Int(floor(rect.minX * k))
+    let pixelX1 = Int(ceil(rect.maxX * k))
+    let pixelY0 = Int(floor((pageHeightPt - rect.maxY) * k))
+    let pixelY1 = Int(ceil((pageHeightPt - rect.minY) * k))
+    return (pixelX0, pixelY0, pixelX1, pixelY1)
+}
+
+@Test("Three-page basic compose")
+func threePageBasicCompose() throws {
+    let directory = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let c1 = makeCapture(sequence: 1, pixelWidth: 1600, pixelHeight: 900)
+    let c2 = makeCapture(sequence: 2, pixelWidth: 900, pixelHeight: 1600)
+    let c3 = makeCapture(sequence: 3, pixelWidth: 1200, pixelHeight: 800)
+    let urls: [UUID: URL] = [
+        c1.id: try writePNG(for: c1, red: 200, green: 20, blue: 20, in: directory),
+        c2.id: try writePNG(for: c2, red: 20, green: 200, blue: 20, in: directory),
+        c3.id: try writePNG(for: c3, red: 20, green: 20, blue: 200, in: directory),
+    ]
+    let session = makeSession(captures: [c1, c2, c3])
+    let output = directory.appendingPathComponent("three.pdf")
+    let pageCount = try PDFComposer().compose(
+        session: session,
+        imageURL: imageURLMap(urls),
+        title: "Three page",
+        to: output
+    )
+    #expect(pageCount == 3)
+    let document = try openDocument(output)
+    #expect(document.pageCount == 3)
+    let p0 = try #require(document.page(at: 0))
+    let p1 = try #require(document.page(at: 1))
+    let p2 = try #require(document.page(at: 2))
+    #expect(p0.bounds(for: .mediaBox) == CGRect(x: 0, y: 0, width: 842, height: 595))
+    #expect(p1.bounds(for: .mediaBox) == CGRect(x: 0, y: 0, width: 595, height: 842))
+    #expect(p2.bounds(for: .mediaBox) == CGRect(x: 0, y: 0, width: 842, height: 595))
+}
+
+@Test("Wide/tall page geometry exact")
+func wideTallPageGeometryExact() throws {
+    let directory = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let wide = makeCapture(sequence: 1, pixelWidth: 1600, pixelHeight: 900)
+    let tall = makeCapture(sequence: 1, pixelWidth: 900, pixelHeight: 1600)
+    let wideURL = try writePNG(for: wide, red: 10, green: 10, blue: 10, in: directory)
+    let tallURL = try writePNG(for: tall, red: 10, green: 10, blue: 10, in: directory)
+
+    let wideOut = directory.appendingPathComponent("wide.pdf")
+    _ = try PDFComposer().compose(
+        session: makeSession(captures: [wide]),
+        imageURL: { _ in wideURL },
+        title: "Wide",
+        to: wideOut
+    )
+    let tallOut = directory.appendingPathComponent("tall.pdf")
+    _ = try PDFComposer().compose(
+        session: makeSession(captures: [tall]),
+        imageURL: { _ in tallURL },
+        title: "Tall",
+        to: tallOut
+    )
+
+    let widePage = try #require(openDocument(wideOut).page(at: 0))
+    let tallPage = try #require(openDocument(tallOut).page(at: 0))
+    #expect(widePage.bounds(for: .mediaBox) == CGRect(x: 0, y: 0, width: 842, height: 595))
+    #expect(tallPage.bounds(for: .mediaBox) == CGRect(x: 0, y: 0, width: 595, height: 842))
+}
+
+@Test("Square resolves to portrait (Capture.swift:39-42 isLandscape strict >)")
+func squareResolvesToPortrait() throws {
+    let directory = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let square = makeCapture(sequence: 1, pixelWidth: 1000, pixelHeight: 1000)
+    let png = try writePNG(for: square, red: 80, green: 80, blue: 80, in: directory)
+    let output = directory.appendingPathComponent("square.pdf")
+    _ = try PDFComposer().compose(
+        session: makeSession(captures: [square]),
+        imageURL: { _ in png },
+        title: "Square",
+        to: output
+    )
+    let page = try #require(openDocument(output).page(at: 0))
+    #expect(page.bounds(for: .mediaBox) == CGRect(x: 0, y: 0, width: 595, height: 842))
+}
+
+@Test("Retina capture uses point size, not pixel size")
+func retinaCaptureUsesPointSize() throws {
+    let capture = makeCapture(sequence: 1, pixelWidth: 2880, pixelHeight: 1620, scale: 2.0)
+    let layout = PageLayout(capture: capture, pageIndex: 1, pageCount: 1)
+    let expectedScale = min(806.0 / 1440.0, 523.0 / 810.0, 1.0)
+    let expected = CGSize(width: 1440.0 * expectedScale, height: 810.0 * expectedScale)
+    #expect(abs(layout.imageRect.width - expected.width) < 0.01)
+    #expect(abs(layout.imageRect.height - expected.height) < 0.01)
+    #expect(layout.imageRect.width < 2000)
+    #expect(layout.isLandscape)
+}
+
+@Test("Zero PDFAnnotation objects on every page")
+func zeroPDFAnnotationObjects() throws {
+    let directory = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let c1 = makeCapture(sequence: 1, pixelWidth: 800, pixelHeight: 600)
+    let c2 = makeCapture(sequence: 2, pixelWidth: 600, pixelHeight: 800)
+    let c3 = makeCapture(sequence: 3, pixelWidth: 1000, pixelHeight: 1000)
+    let urls: [UUID: URL] = [
+        c1.id: try writePNG(for: c1, red: 30, green: 30, blue: 30, in: directory),
+        c2.id: try writePNG(for: c2, red: 40, green: 40, blue: 40, in: directory),
+        c3.id: try writePNG(for: c3, red: 50, green: 50, blue: 50, in: directory),
+    ]
+    let output = directory.appendingPathComponent("no-annots.pdf")
+    _ = try PDFComposer().compose(
+        session: makeSession(captures: [c1, c2, c3]),
+        imageURL: imageURLMap(urls),
+        title: "No annotations",
+        to: output
+    )
+    let document = try openDocument(output)
+    #expect(document.pageCount == 3)
+    for index in 0..<document.pageCount {
+        let page = try #require(document.page(at: index))
+        #expect(page.annotations.isEmpty)
+    }
+}
+
+@Test("Mixed orientations coexist, unnormalised")
+func mixedOrientationsCoexist() throws {
+    let directory = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let wide = makeCapture(sequence: 1, pixelWidth: 1600, pixelHeight: 900)
+    let tall = makeCapture(sequence: 2, pixelWidth: 900, pixelHeight: 1600)
+    let square = makeCapture(sequence: 3, pixelWidth: 1000, pixelHeight: 1000)
+    let urls: [UUID: URL] = [
+        wide.id: try writePNG(for: wide, red: 90, green: 10, blue: 10, in: directory),
+        tall.id: try writePNG(for: tall, red: 10, green: 90, blue: 10, in: directory),
+        square.id: try writePNG(for: square, red: 10, green: 10, blue: 90, in: directory),
+    ]
+    let output = directory.appendingPathComponent("mixed.pdf")
+    _ = try PDFComposer().compose(
+        session: makeSession(captures: [wide, tall, square]),
+        imageURL: imageURLMap(urls),
+        title: "Mixed",
+        to: output
+    )
+    let document = try openDocument(output)
+    #expect(document.pageCount == 3)
+    let p0 = try #require(document.page(at: 0))
+    let p1 = try #require(document.page(at: 1))
+    let p2 = try #require(document.page(at: 2))
+    #expect(p0.bounds(for: .mediaBox) == CGRect(x: 0, y: 0, width: 842, height: 595))
+    #expect(p1.bounds(for: .mediaBox) == CGRect(x: 0, y: 0, width: 595, height: 842))
+    #expect(p2.bounds(for: .mediaBox) == CGRect(x: 0, y: 0, width: 595, height: 842))
+}
+
+@Test("No cover page, no before/after, exactly one page per capture")
+func noCoverPageExactlyOnePagePerCapture() throws {
+    let directory = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let c1 = makeCapture(sequence: 1, pixelWidth: 800, pixelHeight: 500)
+    let c2 = makeCapture(sequence: 2, pixelWidth: 500, pixelHeight: 800)
+    let urls: [UUID: URL] = [
+        c1.id: try writePNG(for: c1, red: 12, green: 12, blue: 12, in: directory),
+        c2.id: try writePNG(for: c2, red: 22, green: 22, blue: 22, in: directory),
+    ]
+    let output = directory.appendingPathComponent("two.pdf")
+    let pageCount = try PDFComposer().compose(
+        session: makeSession(captures: [c1, c2]),
+        imageURL: imageURLMap(urls),
+        title: "Two",
+        to: output
+    )
+    #expect(pageCount == 2)
+    #expect(try openDocument(output).pageCount == 2)
+}
+
+@Test("Small image is never upscaled")
+func smallImageIsNeverUpscaled() throws {
+    let capture = makeCapture(sequence: 1, pixelWidth: 200, pixelHeight: 150)
+    let layout = PageLayout(capture: capture, pageIndex: 1, pageCount: 1)
+    #expect(layout.imageRect.size == CGSize(width: 200, height: 150))
+}
+
+@Test("Empty session throws, produces nothing on disk")
+func emptySessionThrowsProducesNothing() throws {
+    let directory = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let output = directory.appendingPathComponent("empty.pdf")
+    var threwCompositionFailed = false
+    do {
+        _ = try PDFComposer().compose(
+            session: makeSession(captures: []),
+            imageURL: { _ in directory.appendingPathComponent("missing.png") },
+            title: "Empty",
+            to: output
+        )
+    } catch ShotdeckError.pdfCompositionFailed {
+        threwCompositionFailed = true
+    }
+    #expect(threwCompositionFailed)
+    #expect(!FileManager.default.fileExists(atPath: output.path))
+    let leftover = try FileManager.default.contentsOfDirectory(atPath: directory.path)
+    #expect(leftover.isEmpty)
+}
+
+@Test("A missing PNG is skipped, page count drops, document still opens")
+func missingPNGIsSkipped() throws {
+    let directory = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let first = makeCapture(sequence: 1, pixelWidth: 1600, pixelHeight: 900)
+    let missing = makeCapture(sequence: 2, pixelWidth: 800, pixelHeight: 600)
+    let third = makeCapture(sequence: 3, pixelWidth: 900, pixelHeight: 1600)
+    let firstURL = try writePNG(for: first, red: 220, green: 10, blue: 10, in: directory)
+    let thirdURL = try writePNG(for: third, red: 10, green: 10, blue: 220, in: directory)
+    let missingURL = directory.appendingPathComponent("does-not-exist.png")
+    let urls: [UUID: URL] = [
+        first.id: firstURL,
+        missing.id: missingURL,
+        third.id: thirdURL,
+    ]
+    let output = directory.appendingPathComponent("skip-missing.pdf")
+    let pageCount = try PDFComposer().compose(
+        session: makeSession(captures: [first, missing, third]),
+        imageURL: imageURLMap(urls),
+        title: "Skip missing",
+        to: output
+    )
+    #expect(pageCount == 2)
+    let document = try openDocument(output)
+    #expect(document.pageCount == 2)
+    let p0 = try #require(document.page(at: 0))
+    let p1 = try #require(document.page(at: 1))
+    #expect(p0.bounds(for: .mediaBox) == CGRect(x: 0, y: 0, width: 842, height: 595))
+    #expect(p1.bounds(for: .mediaBox) == CGRect(x: 0, y: 0, width: 595, height: 842))
+
+    // Distinct fill colors sampled from pdftoppm at each imageRect center.
+    let prefix = directory.appendingPathComponent("skip-missing")
+    try pdftoppm(pdf: output, prefix: prefix)
+    let page1PNG = directory.appendingPathComponent("skip-missing-1.png")
+    let page2PNG = directory.appendingPathComponent("skip-missing-2.png")
+    let bitmap1 = try RGBABitmap.loadPNG(at: page1PNG)
+    let bitmap2 = try RGBABitmap.loadPNG(at: page2PNG)
+    let k = 110.0 / 72.0
+    let layout1 = PageLayout(capture: first, pageIndex: 1, pageCount: 2)
+    let layout2 = PageLayout(capture: third, pageIndex: 2, pageCount: 2)
+    let c1 = try #require(bitmap1.pixel(
+        x: Int((layout1.imageRect.midX * k).rounded()),
+        y: Int(((layout1.pageRect.height - layout1.imageRect.midY) * k).rounded())
+    ))
+    let c2 = try #require(bitmap2.pixel(
+        x: Int((layout2.imageRect.midX * k).rounded()),
+        y: Int(((layout2.pageRect.height - layout2.imageRect.midY) * k).rounded())
+    ))
+    #expect(c1.0 > 150 && c1.1 < 80 && c1.2 < 80)
+    #expect(c2.2 > 150 && c2.0 < 80 && c2.1 < 80)
+}
+
+@Test("An unreadable (corrupt) PNG is treated exactly like a missing one (D-A)")
+func unreadablePNGIsSkippedLikeMissing() throws {
+    let directory = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let good = makeCapture(sequence: 1, pixelWidth: 800, pixelHeight: 500)
+    let bad = makeCapture(sequence: 2, pixelWidth: 800, pixelHeight: 500)
+    let goodURL = try writePNG(for: good, red: 30, green: 140, blue: 30, in: directory)
+    let badURL = directory.appendingPathComponent("corrupt.png")
+    try Data([0x00, 0x01, 0x02, 0xFF, 0xD8, 0x00]).write(to: badURL)
+    let urls: [UUID: URL] = [good.id: goodURL, bad.id: badURL]
+    let output = directory.appendingPathComponent("skip-corrupt.pdf")
+    let pageCount = try PDFComposer().compose(
+        session: makeSession(captures: [good, bad]),
+        imageURL: imageURLMap(urls),
+        title: "Skip corrupt",
+        to: output
+    )
+    #expect(pageCount == 1)
+    let document = try openDocument(output)
+    #expect(document.pageCount == 1)
+}
+
+@Test("Document attributes round-trip exactly")
+func documentAttributesRoundTrip() throws {
+    let directory = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let sessionID = try #require(UUID(uuidString: "deadbeef-dead-4eef-8ead-deadbeef0001"))
+    let capture = makeCapture(sequence: 1, pixelWidth: 640, pixelHeight: 480)
+    let png = try writePNG(for: capture, red: 40, green: 40, blue: 40, in: directory)
+    let output = directory.appendingPathComponent("attrs.pdf")
+    _ = try PDFComposer().compose(
+        session: makeSession(captures: [capture], id: sessionID),
+        imageURL: { _ in png },
+        title: "Ben review — 2026-08-30",
+        to: output
+    )
+    let document = try openDocument(output)
+    let attributes = try #require(document.documentAttributes)
+    #expect(attributes[PDFDocumentAttribute.creatorAttribute] as? String == "Shotdeck")
+    #expect(attributes[PDFDocumentAttribute.titleAttribute] as? String == "Ben review — 2026-08-30")
+    #expect(attributes[PDFDocumentAttribute.subjectAttribute] as? String == "deadbeef-dead-4eef-8ead-deadbeef0001")
+    #expect(document.pageCount == 1)
+    #expect(try #require(document.page(at: 0)).annotations.isEmpty)
+}
+
+@Test("Rendered page is not blank (pdftoppm, pinned renderer + rounding)")
+func renderedPageIsNotBlank() throws {
+    let directory = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: directory) }
+
+    let capture = makeCapture(sequence: 1, pixelWidth: 1600, pixelHeight: 900)
+    let png = try writePNG(for: capture, red: 128, green: 128, blue: 128, in: directory)
+    let output = directory.appendingPathComponent("not-blank.pdf")
+    _ = try PDFComposer().compose(
+        session: makeSession(captures: [capture]),
+        imageURL: { _ in png },
+        title: "Not blank",
+        to: output
+    )
+    let prefix = directory.appendingPathComponent("not-blank")
+    try pdftoppm(pdf: output, prefix: prefix)
+    let rendered = directory.appendingPathComponent("not-blank-1.png")
+    let bitmap = try RGBABitmap.loadPNG(at: rendered)
+    let layout = PageLayout(capture: capture, pageIndex: 1, pageCount: 1)
+    let k: CGFloat = 110.0 / 72.0
+    let imageWin = pixelWindow(for: layout.imageRect, pageHeightPt: layout.pageRect.height, scale: k)
+    let headerWin = pixelWindow(for: layout.headerRect, pageHeightPt: layout.pageRect.height, scale: k)
+    #expect(bitmap.containsNonWhite(x0: imageWin.x0, y0: imageWin.y0, x1: imageWin.x1, y1: imageWin.y1))
+    #expect(bitmap.containsNonWhite(x0: headerWin.x0, y0: headerWin.y0, x1: headerWin.x1, y1: headerWin.y1))
+}
+
+@Test("Right-edge tick group geometry matches D-12 exactly, both orientations")
+func rightEdgeTickGroupGeometry() throws {
+    let landscape = makeCapture(sequence: 1, pixelWidth: 1600, pixelHeight: 900)
+    let portrait = makeCapture(sequence: 1, pixelWidth: 900, pixelHeight: 1600)
+    let landscapeLayout = PageLayout(capture: landscape, pageIndex: 1, pageCount: 1)
+    let portraitLayout = PageLayout(capture: portrait, pageIndex: 1, pageCount: 1)
+
+    #expect(landscapeLayout.failTickBox.maxX == 824)
+    #expect(landscapeLayout.headerRect.maxX == 824)
+    #expect(portraitLayout.failTickBox.maxX == 577)
+    #expect(portraitLayout.headerRect.maxX == 577)
+    #expect(landscapeLayout.failTickBox.width == 13)
+    #expect(landscapeLayout.failTickBox.height == 13)
+    #expect(portraitLayout.failTickBox.width == 13)
+    #expect(portraitLayout.failTickBox.height == 13)
+    #expect(landscapeLayout.passTickBox.maxX == landscapeLayout.failLabelOrigin.x - 8)
+    #expect(portraitLayout.passTickBox.maxX == portraitLayout.failLabelOrigin.x - 8)
+}
+
+@Test("Writes visual sample for review")
+func writesVisualSampleForReview() throws {
+    let verifyDir = URL(fileURLWithPath: "/Users/benjaminhippler/mmd-projects/multi-agent-runs/shotdeck-20260830/verify")
+    try FileManager.default.createDirectory(at: verifyDir, withIntermediateDirectories: true)
+    let scratch = try makeScratchDirectory()
+    defer { try? FileManager.default.removeItem(at: scratch) }
+
+    let wide = makeCapture(sequence: 1, pixelWidth: 1600, pixelHeight: 900)
+    let tall = makeCapture(sequence: 2, pixelWidth: 900, pixelHeight: 1600)
+    let retina = makeCapture(sequence: 3, pixelWidth: 2880, pixelHeight: 1620, scale: 2.0)
+    let urls: [UUID: URL] = [
+        wide.id: try writePNG(for: wide, red: 196, green: 42, blue: 42, in: scratch),
+        tall.id: try writePNG(for: tall, red: 32, green: 96, blue: 176, in: scratch),
+        retina.id: try writePNG(for: retina, red: 36, green: 148, blue: 84, in: scratch),
+    ]
+    let output = verifyDir.appendingPathComponent("wp2-sample.pdf")
+    let pageCount = try PDFComposer().compose(
+        session: makeSession(captures: [wide, tall, retina]),
+        imageURL: imageURLMap(urls),
+        title: "WP-2 visual sample",
+        to: output
+    )
+    #expect(pageCount == 3)
+    let prefix = verifyDir.appendingPathComponent("wp2-sample")
+    try pdftoppm(pdf: output, prefix: prefix)
+}

Tests/ShotdeckCoreTests/ReturnLedgerTests.swift

@@ -0,0 +1,200 @@
+import Foundation
+import Testing
+import ShotdeckCore
+
+private func makeCasePaths() throws -> (paths: AppSupportPaths, cleanup: URL) {
+    let cleanup = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-wp5a-ledger-\(UUID().uuidString)", isDirectory: true)
+    let paths = try AppSupportPaths(
+        root: cleanup.appendingPathComponent("root", isDirectory: true),
+        outbox: cleanup.appendingPathComponent("outbox", isDirectory: true),
+        watchFolder: cleanup.appendingPathComponent("watch", isDirectory: true)
+    )
+    return (paths, cleanup)
+}
+
+private func document(
+    path: String,
+    annotatedPages: [Int],
+    detectedAt: Date,
+    sessionID: UUID? = nil,
+    pageCount: Int = 1
+) -> ReturnedDocument {
+    ReturnedDocument(
+        fileURL: URL(fileURLWithPath: path),
+        sessionID: sessionID,
+        pageCount: pageCount,
+        annotatedPages: annotatedPages,
+        detectedAt: detectedAt
+    )
+}
+
+@Test("L-1 commented() returns only commented entries, newest first")
+func l1_commentedReturnsOnlyCommentedNewestFirst() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let newer = document(
+        path: "/tmp/shotdeck-returns/newer.pdf",
+        annotatedPages: [1, 2],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_200)
+    )
+    let older = document(
+        path: "/tmp/shotdeck-returns/older.pdf",
+        annotatedPages: [3],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_100)
+    )
+    let clean = document(
+        path: "/tmp/shotdeck-returns/clean.pdf",
+        annotatedPages: [],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_300)
+    )
+
+    let ledger = try ReturnLedger(paths: paths)
+    try await ledger.record(older)
+    try await ledger.record(newer)
+    try await ledger.record(clean)
+
+    let commented = try await ledger.commented()
+    #expect(commented.map(\.fileURL) == [newer.fileURL, older.fileURL])
+    #expect(commented.map(\.annotatedPages) == [[1, 2], [3]])
+}
+
+@Test("L-2 clipboardText() exact format")
+func l2_clipboardTextExactFormat() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let newer = document(
+        path: "/tmp/shotdeck-returns/newer.pdf",
+        annotatedPages: [1, 2],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_200)
+    )
+    let older = document(
+        path: "/tmp/shotdeck-returns/older.pdf",
+        annotatedPages: [3],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_100)
+    )
+    let clean = document(
+        path: "/tmp/shotdeck-returns/clean.pdf",
+        annotatedPages: [],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_300)
+    )
+
+    let ledger = try ReturnLedger(paths: paths)
+    try await ledger.record(older)
+    try await ledger.record(newer)
+    try await ledger.record(clean)
+
+    let text = try await ledger.clipboardText()
+    #expect(text == newer.fileURL.path + "\n" + older.fileURL.path)
+    #expect(text.hasSuffix("\n") == false)
+}
+
+@Test("L-3 Re-recording the same URL upserts")
+func l3_rerecordingTheSameURLUpserts() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let url = URL(fileURLWithPath: "/tmp/shotdeck-returns/same.pdf")
+    let first = ReturnedDocument(
+        fileURL: url,
+        sessionID: nil,
+        pageCount: 1,
+        annotatedPages: [],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_400)
+    )
+    let second = ReturnedDocument(
+        fileURL: url,
+        sessionID: UUID(uuidString: "11111111-1111-1111-1111-111111111111"),
+        pageCount: 1,
+        annotatedPages: [1],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_100)
+    )
+
+    let ledger = try ReturnLedger(paths: paths)
+    try await ledger.record(first)
+    try await ledger.record(second)
+
+    let all = try await ledger.all()
+    #expect(all.count == 1)
+    #expect(all[0].fileURL == url)
+    #expect(all[0].annotatedPages == [1])
+    #expect(all[0].isCommented == true)
+    #expect(all[0].sessionID == UUID(uuidString: "11111111-1111-1111-1111-111111111111"))
+}
+
+@Test("L-4 clipboardText() throws when nothing is commented")
+func l4_clipboardTextThrowsWhenNothingIsCommented() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let ledger = try ReturnLedger(paths: paths)
+    let emptyError = try await #require(throws: ShotdeckError.self) {
+        try await ledger.clipboardText()
+    }
+    guard case .noCommentedReturns = emptyError else {
+        Issue.record("expected noCommentedReturns on an empty ledger, got \(emptyError)")
+        return
+    }
+
+    try await ledger.record(document(
+        path: "/tmp/shotdeck-returns/clean-only.pdf",
+        annotatedPages: [],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_500)
+    ))
+    let cleanError = try await #require(throws: ShotdeckError.self) {
+        try await ledger.clipboardText()
+    }
+    guard case .noCommentedReturns = cleanError else {
+        Issue.record("expected noCommentedReturns with only clean returns, got \(cleanError)")
+        return
+    }
+}
+
+@Test("L-5 Ledger survives reopening from disk")
+func l5_ledgerSurvivesReopeningFromDisk() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let first = document(
+        path: "/tmp/shotdeck-returns/a.pdf",
+        annotatedPages: [1],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_700),
+        sessionID: UUID(uuidString: "11111111-1111-1111-1111-111111111111")
+    )
+    let second = document(
+        path: "/tmp/shotdeck-returns/b.pdf",
+        annotatedPages: [],
+        detectedAt: Date(timeIntervalSince1970: 1_777_000_600)
+    )
+
+    do {
+        let ledger = try ReturnLedger(paths: paths)
+        try await ledger.record(first)
+        try await ledger.record(second)
+    }
+
+    let reopened = try ReturnLedger(paths: paths)
+    let all = try await reopened.all()
+    #expect(all == [first, second])
+}
+
+@Test("L-6 Corrupt returns.json is renamed and the ledger starts empty")
+func l6_corruptReturnsJSONIsRenamedAndStartsEmpty() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let returnsURL = paths.root.appendingPathComponent("returns.json")
+    try Data("{not-json".utf8).write(to: returnsURL)
+    #expect(FileManager.default.fileExists(atPath: returnsURL.path))
+
+    let ledger = try ReturnLedger(paths: paths)
+    #expect(try await ledger.all() == [])
+    #expect(FileManager.default.fileExists(atPath: returnsURL.path) == false)
+
+    let names = try FileManager.default.contentsOfDirectory(atPath: paths.root.path)
+    let corrupt = names.filter { $0.hasPrefix("returns.json.corrupt-") }
+    #expect(corrupt.count == 1)
+    #expect(corrupt[0].contains(DubaiTime.fileStamp(Date()).prefix(8)))
+}

Tests/ShotdeckCoreTests/ReturnWatcherTests.swift

@@ -0,0 +1,173 @@
+import AppKit
+import Foundation
+import PDFKit
+import Testing
+import ShotdeckCore
+
+private let pageBounds = CGRect(x: 0, y: 0, width: 600, height: 800)
+
+private func makeAnnotation(
+    _ subtype: PDFAnnotationSubtype,
+    bounds: CGRect = CGRect(x: 100, y: 100, width: 80, height: 40),
+    contents: String? = nil
+) -> PDFAnnotation {
+    let annotation = PDFAnnotation(
+        bounds: bounds,
+        forType: subtype,
+        withProperties: nil
+    )
+    annotation.contents = contents
+    return annotation
+}
+
+private func makePDF(
+    at url: URL,
+    pageCount: Int,
+    creator: String? = "Shotdeck",
+    subject: String? = nil,
+    annotations: [(page: Int, annotation: PDFAnnotation)] = []
+) throws {
+    let document = PDFDocument()
+    for index in 0..<pageCount {
+        let page = PDFPage()
+        page.setBounds(pageBounds, for: .mediaBox)
+        document.insert(page, at: index)
+    }
+
+    var attributes = [PDFDocumentAttribute: Any]()
+    if let creator { attributes[.creatorAttribute] = creator }
+    if let subject { attributes[.subjectAttribute] = subject }
+    document.documentAttributes = attributes
+
+    for item in annotations {
+        guard let page = document.page(at: item.page) else {
+            throw NSError(domain: "WP5Test", code: 1)
+        }
+        page.addAnnotation(item.annotation)
+    }
+
+    guard document.write(to: url) else {
+        throw NSError(domain: "WP5Test", code: 2)
+    }
+}
+
+private func makeCasePaths() throws -> (paths: AppSupportPaths, cleanup: URL) {
+    let cleanup = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-wp5b-\(UUID().uuidString)", isDirectory: true)
+    let paths = try AppSupportPaths(
+        root: cleanup.appendingPathComponent("root", isDirectory: true),
+        outbox: cleanup.appendingPathComponent("outbox", isDirectory: true),
+        watchFolder: cleanup.appendingPathComponent("watch", isDirectory: true)
+    )
+    return (paths, cleanup)
+}
+
+/// Guards `confirmation(expectedCount: 1)` against a create+rename double-event.
+private final class ConfirmOnce: @unchecked Sendable {
+    private let lock = NSLock()
+    private var fired = false
+    func run(_ body: () -> Void) {
+        lock.lock()
+        defer { lock.unlock() }
+        guard !fired else { return }
+        fired = true
+        body()
+    }
+}
+
+@Test("W-25 Duplicate-name suffix is the normal AirDrop return (scanNow)")
+func w25_duplicateNameSuffixIsRecognizedByScanNow() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let ledger = try ReturnLedger(paths: paths)
+    let watcher = ReturnWatcher(paths: paths, ledger: ledger)
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134205 2.pdf")
+
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        creator: nil,
+        subject: "33333333-3333-3333-3333-333333333333",
+        annotations: [(page: 0, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 100, y: 100, width: 120, height: 50)
+        ))]
+    )
+
+    let found = try await watcher.scanNow()
+    #expect(found.count == 1)
+    let doc = try #require(found.first)
+    #expect(doc.fileURL.lastPathComponent == "Shotdeck-20260830-134205 2.pdf")
+    #expect(doc.fileURL.resolvingSymlinksInPath().path == pdfURL.resolvingSymlinksInPath().path)
+    #expect(doc.pageCount == 1)
+    #expect(doc.annotatedPages == [1])
+    #expect(doc.isCommented == true)
+
+    let commented = try await ledger.commented()
+    #expect(commented.count == 1)
+    #expect(commented[0].fileURL.lastPathComponent == pdfURL.lastPathComponent)
+    #expect(commented[0].fileURL.resolvingSymlinksInPath().path == pdfURL.resolvingSymlinksInPath().path)
+}
+
+@Test("W-26 Creator provenance negative at the scan level")
+func w26_presentNonShotdeckCreatorIsIgnoredByScanNow() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let ledger = try ReturnLedger(paths: paths)
+    let watcher = ReturnWatcher(paths: paths, ledger: ledger)
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-134218.pdf")
+
+    try makePDF(
+        at: pdfURL,
+        pageCount: 1,
+        creator: "Preview",
+        annotations: [(page: 0, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 100, y: 100, width: 120, height: 50)
+        ))]
+    )
+
+    let found = try await watcher.scanNow()
+    #expect(found.isEmpty)
+    let all = try await ledger.all()
+    #expect(all.isEmpty)
+}
+
+@Test("W-27 FSEvents live callback fires on a real file arrival")
+func w27_fsEventsCallbackFiresOnRealArrival() async throws {
+    let (paths, cleanup) = try makeCasePaths()
+    defer { try? FileManager.default.removeItem(at: cleanup) }
+
+    let ledger = try ReturnLedger(paths: paths)
+    let watcher = ReturnWatcher(paths: paths, ledger: ledger)
+    let pdfURL = paths.watchFolder.appendingPathComponent("Shotdeck-20260830-140000.pdf")
+    let once = ConfirmOnce()
+
+    try await confirmation("watcher reports the arrived PDF", expectedCount: 1) { confirm in
+        do {
+            try await watcher.start { docs in
+                if docs.contains(where: { $0.fileURL.lastPathComponent == pdfURL.lastPathComponent }) {
+                    once.run { confirm() }
+                }
+            }
+            // Simulate AirDrop's own write-then-rename so the watcher must survive that pattern.
+            let tmpURL = pdfURL.appendingPathExtension("inprogress")
+            try makePDF(
+                at: tmpURL, pageCount: 1, creator: "Shotdeck",
+                annotations: [(page: 0, annotation: makeAnnotation(
+                    .ink, bounds: CGRect(x: 100, y: 100, width: 120, height: 50)
+                ))]
+            )
+            try FileManager.default.moveItem(at: tmpURL, to: pdfURL)
+        } catch {
+            print("fsEventsCallbackFiresOnRealArrival error: \(error)")
+            await watcher.stop()
+            throw error
+        }
+        // Budget: 400ms debounce + FS latency + the 250ms stability re-read + PDFKit open.
+        // 5s is a generous, fixed ceiling — never a "some time" wait.
+        try await Task.sleep(for: .seconds(5))
+        await watcher.stop()
+        await watcher.stop()
+    }
+}

Tests/ShotdeckCoreTests/SpoolStoreTests.swift

@@ -0,0 +1,590 @@
+import CoreGraphics
+import Foundation
+import ImageIO
+import Testing
+import ShotdeckCore
+
+// MARK: - 1. append writes a real, decodable PNG
+
+@Test
+func appendWritesARealDecodablePNGMatchingSourceDimensions() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let width = 12
+    let height = 7
+    let png = try makePNGData(width: width, height: height, red: 0.9, green: 0.1, blue: 0.2)
+    let store = try SpoolStore(paths: paths)
+    let capturedAt = Date(timeIntervalSince1970: 1_700_000_000)
+    let capture = try await store.append(
+        pngData: png, pixelWidth: width, pixelHeight: height, scale: 2.0, capturedAt: capturedAt)
+    let session = try await store.currentSession()
+
+    #expect(capture.pixelWidth == width)
+    #expect(capture.pixelHeight == height)
+
+    let url = await store.imageURL(for: capture, in: session)
+    let expected = paths.sessionDirectory(session.id).appendingPathComponent(capture.fileName)
+    #expect(url.path == expected.path)
+    #expect(FileManager.default.fileExists(atPath: url.path))
+
+    let onDisk = try Data(contentsOf: url)
+    #expect(onDisk == png)
+    let decoded = try #require(pngDimensions(at: url))
+    #expect(decoded.width == width)
+    #expect(decoded.height == height)
+}
+
+// MARK: - 2. remaining-manifest sequence rule (coordinator correction)
+
+@Test
+func sequencesFollowRemainingManifestMaxAndAreNotRenumbered() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let c1 = try await store.append(
+        pngData: try makePNGData(width: 4, height: 4, red: 1, green: 0, blue: 0),
+        pixelWidth: 4, pixelHeight: 4, scale: 1.0, capturedAt: Date())
+    let c2 = try await store.append(
+        pngData: try makePNGData(width: 6, height: 4, red: 0, green: 1, blue: 0),
+        pixelWidth: 6, pixelHeight: 4, scale: 1.0, capturedAt: Date())
+    let c3 = try await store.append(
+        pngData: try makePNGData(width: 8, height: 4, red: 0, green: 0, blue: 1),
+        pixelWidth: 8, pixelHeight: 4, scale: 1.0, capturedAt: Date())
+    #expect(c1.sequence == 1)
+    #expect(c2.sequence == 2)
+    #expect(c3.sequence == 3)
+
+    _ = try await store.remove(captureID: c2.id)
+    let afterMiddle = try await store.currentSession()
+    #expect(afterMiddle.captures.map(\.sequence) == [1, 3])
+    #expect(afterMiddle.captures.map(\.id) == [c1.id, c3.id])
+
+    let c4 = try await store.append(
+        pngData: try makePNGData(width: 10, height: 4, red: 1, green: 1, blue: 0),
+        pixelWidth: 10, pixelHeight: 4, scale: 1.0, capturedAt: Date())
+    #expect(c4.sequence == 4)
+
+    _ = try await store.remove(captureID: c4.id)
+    let afterLast = try await store.currentSession()
+    #expect(afterLast.captures.map(\.sequence) == [1, 3])
+
+    let c4b = try await store.append(
+        pngData: try makePNGData(width: 12, height: 4, red: 1, green: 0, blue: 1),
+        pixelWidth: 12, pixelHeight: 4, scale: 1.0, capturedAt: Date())
+    #expect(c4b.sequence == 4)
+    #expect(c4b.fileName != c4.fileName)
+    #expect(c4b.id != c4.id)
+
+    let sessionDir = paths.sessionDirectory(afterLast.id)
+    #expect(FileManager.default.fileExists(atPath: sessionDir.appendingPathComponent(c4b.fileName).path))
+    #expect(FileManager.default.fileExists(
+        atPath: sessionDir.appendingPathComponent("removed", isDirectory: true)
+            .appendingPathComponent(c4.fileName).path))
+    #expect(!FileManager.default.fileExists(atPath: sessionDir.appendingPathComponent(c4.fileName).path))
+}
+
+// MARK: - 3. remove moves PNG into removed/
+
+@Test
+func removeMovesThePNGUnchangedIntoRemovedAndLeavesTheOriginalPathEmpty() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let png = try makePNGData(width: 8, height: 5, red: 0.2, green: 0.5, blue: 0.8)
+    let capture = try await store.append(
+        pngData: png, pixelWidth: 8, pixelHeight: 5, scale: 2.0, capturedAt: Date())
+    let session = try await store.currentSession()
+    let sessionDir = paths.sessionDirectory(session.id)
+    let originalURL = sessionDir.appendingPathComponent(capture.fileName)
+    let removedURL = sessionDir.appendingPathComponent("removed", isDirectory: true)
+        .appendingPathComponent(capture.fileName)
+
+    let updated = try await store.remove(captureID: capture.id)
+
+    #expect(updated.captures.contains(where: { $0.id == capture.id }) == false)
+    #expect(!FileManager.default.fileExists(atPath: originalURL.path))
+    #expect(FileManager.default.fileExists(atPath: removedURL.path))
+    let moved = try Data(contentsOf: removedURL)
+    #expect(moved == png)
+}
+
+// MARK: - 4. remove of unknown id throws with zero filesystem change
+
+@Test
+func removeOfUnknownIDThrowsAndLeavesDiskByteIdentical() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    _ = try await store.append(
+        pngData: try makePNGData(width: 4, height: 4, red: 0.1, green: 0.2, blue: 0.3),
+        pixelWidth: 4, pixelHeight: 4, scale: 1.0, capturedAt: Date())
+    let beforeSession = try await store.currentSession()
+    let beforeFiles = try snapshotFiles(under: root)
+
+    do {
+        _ = try await store.remove(captureID: UUID())
+        Issue.record("expected remove of an unknown id to throw")
+    } catch let error as ShotdeckError {
+        guard case .spoolWriteFailed = error else {
+            Issue.record("expected spoolWriteFailed, got \(error)")
+            return
+        }
+    } catch {
+        Issue.record("expected ShotdeckError, got \(error)")
+        return
+    }
+
+    let afterSession = try await store.currentSession()
+    #expect(afterSession == beforeSession)
+    let afterFiles = try snapshotFiles(under: root)
+    #expect(afterFiles == beforeFiles)
+}
+
+// MARK: - 5. orphan recovery
+
+@Test
+func orphanPNGWrittenBehindTheStoreIsRecoveredOnReopen() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let session = try await store.currentSession()
+    let width = 11
+    let height = 9
+    let png = try makePNGData(width: width, height: height, red: 0.4, green: 0.7, blue: 0.1)
+    let orphanName = "007-ABCD1234.png"
+    let dest = paths.sessionDirectory(session.id).appendingPathComponent(orphanName)
+    try AtomicFile.write(png, to: dest)
+
+    let reopened = try SpoolStore(paths: paths)
+    let recovered = try await reopened.currentSession()
+    let match = try #require(recovered.captures.first { $0.fileName == orphanName })
+    #expect(match.pixelWidth == width)
+    #expect(match.pixelHeight == height)
+    #expect(match.sequence == 7)
+    #expect(match.scale == 1.0)
+}
+
+// MARK: - 6. removed/ files are not resurrected
+
+@Test
+func orphanRecoveryDoesNotResurrectFilesInRemoved() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let session = try await store.currentSession()
+    let sessionDir = paths.sessionDirectory(session.id)
+    let removedDir = sessionDir.appendingPathComponent("removed", isDirectory: true)
+    try FileManager.default.createDirectory(at: removedDir, withIntermediateDirectories: true)
+    let hiddenName = "009-FEEDFACE.png"
+    try AtomicFile.write(
+        try makePNGData(width: 5, height: 5, red: 0.9, green: 0.9, blue: 0.1),
+        to: removedDir.appendingPathComponent(hiddenName))
+
+    let reopened = try SpoolStore(paths: paths)
+    let reconciled = try await reopened.currentSession()
+    #expect(reconciled.captures.contains(where: { $0.fileName == hiddenName }) == false)
+    #expect(FileManager.default.fileExists(atPath: removedDir.appendingPathComponent(hiddenName).path))
+}
+
+// MARK: - 7. missing-image drop
+
+@Test
+func missingPNGReferencedByManifestIsDroppedAndOthersSurvive() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let keep = try await store.append(
+        pngData: try makePNGData(width: 6, height: 6, red: 0.1, green: 0.8, blue: 0.2),
+        pixelWidth: 6, pixelHeight: 6, scale: 1.0, capturedAt: Date())
+    let drop = try await store.append(
+        pngData: try makePNGData(width: 7, height: 7, red: 0.8, green: 0.1, blue: 0.2),
+        pixelWidth: 7, pixelHeight: 7, scale: 1.0, capturedAt: Date())
+    let session = try await store.currentSession()
+    try FileManager.default.removeItem(
+        at: paths.sessionDirectory(session.id).appendingPathComponent(drop.fileName))
+
+    let reopened = try SpoolStore(paths: paths)
+    let reconciled = try await reopened.currentSession()
+    #expect(reconciled.captures.map(\.id) == [keep.id])
+    #expect(reconciled.captures.contains(where: { $0.id == drop.id }) == false)
+}
+
+// MARK: - 8. corrupt manifest rebuild
+
+@Test
+func corruptManifestIsQuarantinedAndPNGsAreRebuiltIntoANewManifest() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let first = try await store.append(
+        pngData: try makePNGData(width: 8, height: 6, red: 0.3, green: 0.3, blue: 0.9),
+        pixelWidth: 8, pixelHeight: 6, scale: 2.0, capturedAt: Date())
+    let second = try await store.append(
+        pngData: try makePNGData(width: 9, height: 6, red: 0.9, green: 0.3, blue: 0.3),
+        pixelWidth: 9, pixelHeight: 6, scale: 2.0, capturedAt: Date())
+    let session = try await store.currentSession()
+    let sessionDir = paths.sessionDirectory(session.id)
+    let manifestURL = sessionDir.appendingPathComponent("session.json")
+    let garbage = Data("{ not json".utf8)
+    try AtomicFile.write(garbage, to: manifestURL)
+
+    let reopened = try SpoolStore(paths: paths)
+    let rebuilt = try await reopened.currentSession()
+    #expect(rebuilt.id == session.id)
+
+    let contents = try FileManager.default.contentsOfDirectory(at: sessionDir, includingPropertiesForKeys: nil)
+    let corruptFiles = contents.filter { $0.lastPathComponent.hasPrefix("session.json.corrupt-") }
+    #expect(corruptFiles.count == 1)
+    let quarantined = try Data(contentsOf: try #require(corruptFiles.first))
+    #expect(quarantined == garbage)
+
+    let names = Set(rebuilt.captures.map(\.fileName))
+    #expect(names.contains(first.fileName))
+    #expect(names.contains(second.fileName))
+    let recoveredFirst = try #require(rebuilt.captures.first { $0.fileName == first.fileName })
+    #expect(recoveredFirst.pixelWidth == 8)
+    #expect(recoveredFirst.pixelHeight == 6)
+}
+
+// MARK: - 9. archiveCurrent moves the directory
+
+@Test
+func archiveCurrentMovesTheSessionUnderArchiveAndOpensAFreshEmptySession() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let png = try makePNGData(width: 10, height: 8, red: 0.5, green: 0.1, blue: 0.6)
+    let capture = try await store.append(
+        pngData: png, pixelWidth: 10, pixelHeight: 8, scale: 1.0, capturedAt: Date())
+    let open = try await store.currentSession()
+    let archived = try await store.archiveCurrent(pdfFileName: "shotdeck-review.pdf")
+
+    #expect(archived.state == .archived)
+    #expect(archived.pdfFileName == "shotdeck-review.pdf")
+    #expect(archived.id == open.id)
+    #expect(!FileManager.default.fileExists(atPath: paths.sessionDirectory(open.id).path))
+
+    let archivedPNG = paths.archiveDirectory(open.id).appendingPathComponent(capture.fileName)
+    #expect(FileManager.default.fileExists(atPath: archivedPNG.path))
+    #expect(try Data(contentsOf: archivedPNG) == png)
+
+    let current = try await store.currentSession()
+    #expect(current.id != open.id)
+    #expect(current.isEmpty)
+    #expect(current.state == .open)
+    #expect(FileManager.default.fileExists(
+        atPath: paths.sessionDirectory(current.id).appendingPathComponent("session.json").path))
+}
+
+// MARK: - 10. archiveCurrent on empty throws
+
+@Test
+func archiveCurrentOnEmptySessionThrowsAndDoesNotMoveTheDirectory() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let session = try await store.currentSession()
+    let before = try snapshotFiles(under: root)
+
+    do {
+        _ = try await store.archiveCurrent(pdfFileName: "never.pdf")
+        Issue.record("expected archiveCurrent on an empty session to throw")
+    } catch let error as ShotdeckError {
+        guard case .spoolWriteFailed = error else {
+            Issue.record("expected spoolWriteFailed, got \(error)")
+            return
+        }
+    } catch {
+        Issue.record("expected ShotdeckError, got \(error)")
+        return
+    }
+
+    #expect(FileManager.default.fileExists(atPath: paths.sessionDirectory(session.id).path))
+    #expect(try snapshotFiles(under: root) == before)
+}
+
+// MARK: - 11. interrupted-archive, both exist
+
+@Test
+func interruptedArchiveBothExistSupersedesTheSpoolCopyAndKeepsArchive() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let png = try makePNGData(width: 8, height: 8, red: 0.2, green: 0.2, blue: 0.8)
+    let capture = try await store.append(
+        pngData: png, pixelWidth: 8, pixelHeight: 8, scale: 1.0, capturedAt: Date())
+    let archived = try await store.archiveCurrent(pdfFileName: "sent.pdf")
+    let archiveDir = paths.archiveDirectory(archived.id)
+    let spoolCopy = paths.sessionDirectory(archived.id)
+    try FileManager.default.copyItem(at: archiveDir, to: spoolCopy)
+    let archivePNGBefore = try Data(contentsOf: archiveDir.appendingPathComponent(capture.fileName))
+
+    let reopened = try SpoolStore(paths: paths)
+    _ = try await reopened.currentSession()
+
+    #expect(FileManager.default.fileExists(atPath: archiveDir.path))
+    #expect(!FileManager.default.fileExists(atPath: spoolCopy.path))
+    #expect(try Data(contentsOf: archiveDir.appendingPathComponent(capture.fileName)) == archivePNGBefore)
+
+    let spoolEntries = try FileManager.default.contentsOfDirectory(
+        at: paths.spool, includingPropertiesForKeys: [.isDirectoryKey])
+    let superseded = spoolEntries.filter {
+        $0.lastPathComponent.hasPrefix("\(archived.id.uuidString).superseded-")
+    }
+    #expect(superseded.count == 1)
+    let supersededPNG = try #require(superseded.first).appendingPathComponent(capture.fileName)
+    #expect(FileManager.default.fileExists(atPath: supersededPNG.path))
+    #expect(try Data(contentsOf: supersededPNG) == png)
+}
+
+// MARK: - 12. interrupted-archive, manifest-only
+
+@Test
+func interruptedArchiveManifestOnlyCompletesTheMoveIntoArchive() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let png = try makePNGData(width: 6, height: 8, red: 0.7, green: 0.4, blue: 0.1)
+    let capture = try await store.append(
+        pngData: png, pixelWidth: 6, pixelHeight: 8, scale: 1.0, capturedAt: Date())
+    let session = try await store.currentSession()
+    let marked = session.markArchived(pdfFileName: "partial.pdf")
+    try AtomicFile.writeJSON(
+        marked, to: paths.sessionDirectory(session.id).appendingPathComponent("session.json"))
+
+    let reopened = try SpoolStore(paths: paths)
+    let current = try await reopened.currentSession()
+    #expect(current.id != session.id)
+    #expect(!FileManager.default.fileExists(atPath: paths.sessionDirectory(session.id).path))
+    let archiveDir = paths.archiveDirectory(session.id)
+    #expect(FileManager.default.fileExists(atPath: archiveDir.path))
+    #expect(FileManager.default.fileExists(atPath: archiveDir.appendingPathComponent(capture.fileName).path))
+    #expect(try Data(contentsOf: archiveDir.appendingPathComponent(capture.fileName)) == png)
+
+    let archived = try await reopened.archivedSessions()
+    #expect(archived.contains(where: { $0.id == session.id }))
+}
+
+// MARK: - 13. archivedSessions newest createdAt first
+
+@Test
+func archivedSessionsReturnsNewestCreatedAtFirst() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let newest = UUID(uuidString: "00000000-0000-4000-8000-000000000003")!
+    let oldest = UUID(uuidString: "00000000-0000-4000-8000-000000000001")!
+    let middle = UUID(uuidString: "00000000-0000-4000-8000-000000000002")!
+    let tNewest = Date(timeIntervalSince1970: 1_700_000_200)
+    let tOldest = Date(timeIntervalSince1970: 1_700_000_000)
+    let tMiddle = Date(timeIntervalSince1970: 1_700_000_100)
+
+    try seedSession(id: newest, createdAt: tNewest, state: .archived, directory: paths.archiveDirectory(newest))
+    try seedSession(id: oldest, createdAt: tOldest, state: .archived, directory: paths.archiveDirectory(oldest))
+    try seedSession(id: middle, createdAt: tMiddle, state: .archived, directory: paths.archiveDirectory(middle))
+
+    let store = try SpoolStore(paths: paths)
+    let listed = try await store.archivedSessions()
+    #expect(listed.map(\.id) == [newest, middle, oldest])
+}
+
+// MARK: - 14. newest-session tie-break by greater UUID string
+
+@Test
+func newestSessionTieBreakPicksTheLexicographicallyGreaterUUID() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let smaller = UUID(uuidString: "AAAAAAAA-AAAA-4AAA-8AAA-AAAAAAAAAAAA")!
+    let greater = UUID(uuidString: "BBBBBBBB-BBBB-4BBB-8BBB-BBBBBBBBBBBB")!
+    let createdAt = Date(timeIntervalSince1970: 1_700_000_500)
+    try seedSession(id: smaller, createdAt: createdAt, state: .open, directory: paths.sessionDirectory(smaller))
+    try seedSession(id: greater, createdAt: createdAt, state: .open, directory: paths.sessionDirectory(greater))
+
+    let first = try SpoolStore(paths: paths)
+    let firstID = try await first.currentSession().id
+    let second = try SpoolStore(paths: paths)
+    let secondID = try await second.currentSession().id
+    #expect(firstID == greater)
+    #expect(secondID == greater)
+}
+
+// MARK: - 15. filename shape
+
+@Test
+func appendFilenameMatchesSequenceDashEightHexSuffix() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let capture = try await store.append(
+        pngData: try makePNGData(width: 4, height: 3, red: 0.1, green: 0.1, blue: 0.1),
+        pixelWidth: 4, pixelHeight: 3, scale: 1.0, capturedAt: Date())
+    let hex = String(capture.id.uuidString.replacingOccurrences(of: "-", with: "").prefix(8)).uppercased()
+    #expect(capture.fileName == "001-\(hex).png")
+    let session = try await store.currentSession()
+    let url = await store.imageURL(for: capture, in: session)
+    #expect(url.lastPathComponent == capture.fileName)
+    #expect(FileManager.default.fileExists(atPath: url.path))
+}
+
+// MARK: - 16. startNewSession
+
+@Test
+func startNewSessionThrowsWhenNonEmptyAndMintsANewIdWhenEmpty() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    _ = try await store.append(
+        pngData: try makePNGData(width: 5, height: 5, red: 0.4, green: 0.2, blue: 0.6),
+        pixelWidth: 5, pixelHeight: 5, scale: 1.0, capturedAt: Date())
+    let before = try snapshotFiles(under: root)
+    let occupied = try await store.currentSession()
+
+    do {
+        _ = try await store.startNewSession()
+        Issue.record("expected startNewSession to throw while captures are present")
+    } catch let error as ShotdeckError {
+        guard case .spoolWriteFailed = error else {
+            Issue.record("expected spoolWriteFailed, got \(error)")
+            return
+        }
+    } catch {
+        Issue.record("expected ShotdeckError, got \(error)")
+        return
+    }
+    #expect(try snapshotFiles(under: root) == before)
+    #expect(try await store.currentSession().id == occupied.id)
+
+    _ = try await store.remove(captureID: occupied.captures[0].id)
+    let emptyID = try await store.currentSession().id
+    let fresh = try await store.startNewSession()
+    #expect(fresh.id != emptyID)
+    #expect(fresh.isEmpty)
+    #expect(FileManager.default.fileExists(
+        atPath: paths.sessionDirectory(emptyID).appendingPathComponent("session.json").path))
+}
+
+// MARK: - 17. durability-ordering smoke test
+
+@Test
+func appendReturnsOnlyAfterThePNGBytesAreAlreadyOnDisk() async throws {
+    let (root, paths) = try makeIsolatedPaths()
+    defer { try? FileManager.default.removeItem(at: root) }
+
+    let store = try SpoolStore(paths: paths)
+    let png = try makePNGData(width: 13, height: 11, red: 0.15, green: 0.55, blue: 0.95)
+    let capture = try await store.append(
+        pngData: png, pixelWidth: 13, pixelHeight: 11, scale: 2.0, capturedAt: Date())
+    let session = try await store.currentSession()
+    let url = paths.sessionDirectory(session.id).appendingPathComponent(capture.fileName)
+    let onDisk = try Data(contentsOf: url)
+    #expect(onDisk == png)
+}
+
+// MARK: - Fixtures
+
+private func makeIsolatedPaths() throws -> (root: URL, paths: AppSupportPaths) {
+    let root = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-spool-\(UUID().uuidString)", isDirectory: true)
+    let paths = try AppSupportPaths(
+        root: root,
+        outbox: root.appendingPathComponent("outbox", isDirectory: true),
+        watchFolder: root.appendingPathComponent("watch", isDirectory: true)
+    )
+    return (root, paths)
+}
+
+private func makePNGData(
+    width: Int,
+    height: Int,
+    red: CGFloat,
+    green: CGFloat,
+    blue: CGFloat
+) throws -> Data {
+    let colorSpace = CGColorSpaceCreateDeviceRGB()
+    guard let context = CGContext(
+        data: nil,
+        width: width,
+        height: height,
+        bitsPerComponent: 8,
+        bytesPerRow: width * 4,
+        space: colorSpace,
+        bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue
+    ) else {
+        throw FixtureError.pngGenerationFailed
+    }
+    context.setFillColor(red: red, green: green, blue: blue, alpha: 1)
+    context.fill(CGRect(x: 0, y: 0, width: width, height: height))
+    guard let image = context.makeImage() else {
+        throw FixtureError.pngGenerationFailed
+    }
+    let buffer = NSMutableData()
+    guard let destination = CGImageDestinationCreateWithData(buffer, "public.png" as CFString, 1, nil) else {
+        throw FixtureError.pngGenerationFailed
+    }
+    CGImageDestinationAddImage(destination, image, nil)
+    guard CGImageDestinationFinalize(destination) else {
+        throw FixtureError.pngGenerationFailed
+    }
+    return buffer as Data
+}
+
+private func pngDimensions(at url: URL) -> (width: Int, height: Int)? {
+    guard let source = CGImageSourceCreateWithURL(url as CFURL, nil),
+          let properties = CGImageSourceCopyPropertiesAtIndex(source, 0, nil) as NSDictionary?,
+          let width = (properties[kCGImagePropertyPixelWidth] as? NSNumber)?.intValue,
+          let height = (properties[kCGImagePropertyPixelHeight] as? NSNumber)?.intValue
+    else { return nil }
+    return (width, height)
+}
+
+private func seedSession(
+    id: UUID,
+    createdAt: Date,
+    state: SessionState,
+    directory: URL
+) throws {
+    try FileManager.default.createDirectory(at: directory, withIntermediateDirectories: true)
+    let session = CaptureSession(id: id, createdAt: createdAt, state: state, captures: [], pdfFileName: nil)
+    try AtomicFile.writeJSON(session, to: directory.appendingPathComponent("session.json"))
+}
+
+private func snapshotFiles(under root: URL) throws -> [String: Data] {
+    let fm = FileManager.default
+    var files: [String: Data] = [:]
+    guard let enumerator = fm.enumerator(
+        at: root,
+        includingPropertiesForKeys: [.isRegularFileKey],
+        options: [.skipsHiddenFiles]
+    ) else { return files }
+    let rootPath = root.standardizedFileURL.path
+    for case let url as URL in enumerator {
+        let values = try url.resourceValues(forKeys: [.isRegularFileKey])
+        guard values.isRegularFile == true else { continue }
+        var relative = url.standardizedFileURL.path
+        if relative.hasPrefix(rootPath) {
+            relative = String(relative.dropFirst(rootPath.count))
+            if relative.hasPrefix("/") { relative = String(relative.dropFirst()) }
+        }
+        files[relative] = try Data(contentsOf: url)
+    }
+    return files
+}
+
+private enum FixtureError: Error {
+    case pngGenerationFailed
+}

scripts/build-app.sh

@@ -0,0 +1,73 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+# macOS keys the Screen Recording permission to the bundle identifier plus the
+# code signature. The identity below and --identifier ai.flowmaster.shotdeck must
+# never change: altering either one makes the existing grant invalid and forces
+# the user to approve Screen Recording again by hand.
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$ROOT"
+
+IDENTITY="Apple Development: ben@flow-master.ai (QH2H9G2LK5)"
+BUNDLE_ID="ai.flowmaster.shotdeck"
+APP_BUNDLE="${ROOT}/.build/Shotdeck.app"
+
+SKIP_SIGN=0
+for arg in "$@"; do
+    case "${arg}" in
+        --skip-sign)
+            SKIP_SIGN=1
+            ;;
+        *)
+            echo "Unknown argument: ${arg}" >&2
+            echo "Usage: $0 [--skip-sign]" >&2
+            exit 1
+            ;;
+    esac
+done
+
+echo "==> Building Shotdeck (release)"
+swift build -c release --product Shotdeck
+
+BIN_PATH="$(swift build -c release --product Shotdeck --show-bin-path)/Shotdeck"
+if [[ ! -x "${BIN_PATH}" ]]; then
+    echo "Release binary not found at ${BIN_PATH}" >&2
+    exit 1
+fi
+
+echo "==> Assembling ${APP_BUNDLE}"
+rm -rf "${APP_BUNDLE}"
+mkdir -p "${APP_BUNDLE}/Contents/MacOS"
+mkdir -p "${APP_BUNDLE}/Contents/Resources"
+cp "${BIN_PATH}" "${APP_BUNDLE}/Contents/MacOS/Shotdeck"
+chmod +x "${APP_BUNDLE}/Contents/MacOS/Shotdeck"
+cp "${ROOT}/Info.plist" "${APP_BUNDLE}/Contents/Info.plist"
+
+if [[ "${SKIP_SIGN}" -eq 1 ]]; then
+    echo
+    echo "************************************************************************"
+    echo "WARNING: --skip-sign was used. This app is UNSIGNED."
+    echo "The resulting app will trigger a fresh Screen Recording prompt and must"
+    echo "not be handed to the user."
+    echo "************************************************************************"
+    echo
+else
+    if ! security find-identity -v -p codesigning | grep -Fq "${IDENTITY}"; then
+        echo "The codesigning identity '${IDENTITY}' is not in this shell's keychain search list." >&2
+        echo "The login keychain is not reachable from this shell." >&2
+        echo "Run this script from a normal login session so the app can be signed." >&2
+        echo "Refusing to produce an unsigned app." >&2
+        exit 1
+    fi
+
+    echo "==> Signing ${APP_BUNDLE}"
+    codesign --force --options runtime \
+        --sign "${IDENTITY}" \
+        --identifier "${BUNDLE_ID}" \
+        "${APP_BUNDLE}"
+fi
+
+echo
+echo "App path: ${APP_BUNDLE}"
+echo "Launch with: open ${APP_BUNDLE}"