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

Sources/Shotdeck/AppModel.swift

@@ -0,0 +1,265 @@
+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/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

@@ -1,6 +1,75 @@
 import AppKit
+import SwiftUI
+import ShotdeckCore
 
-// WP-4 replaces this body with the real menu-bar UI.
+// SwiftPM treats a file named main.swift as top-level code, which forbids `@main`.
-let application = NSApplication.shared
+// App.main() is the equivalent entry point.
-application.setActivationPolicy(.accessory)
+ShotdeckApp.main()
-application.run()
+
+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/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()
+}

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()
+    }
+}