test(update-checker): rewrite tests to exercise real production code

REPLACED: three worthless tests that only tested test code, not production:
- statusMessageUpToDateFormat built the expected string locally and matched it
- statusMessageUpdateReadyFormat same self-referential test
- statusChannelsAreIndependent was literally #expect(true, ...)

ADDED: four real tests that drive production code:
- dubaiTimeCheckTimeFormat: assert DubaiTime.checkTime() formats as HH:MM Dubai
- manualCheckUpToDateIncludesTimestamp: inject stub appcast via testAppcastJSON seam,
  drive UpdateChecker.checkNow(manual: true), verify statusMessage matches exact format
- automaticCheckUpToDateLeavesMessageNil: verify automatic check (manual: false) leaves
  statusMessage nil when up-to-date
- statusChannelsAreIndependent: construct real AppModel via AppDelegate.makeLaunchModel(),
  assert setStatus() does NOT affect updateStatusMessage, setUpdateStatus() does NOT
  affect statusLine, and vice versa. PROVES the defect is caught: test fails with 3 issues
  if updateStatusMessage is reverted to an alias of statusLine.

ADDED: testAppcastJSON seam to UpdateChecker for test injection of appcast data.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012ZiTXPbPCSjzPVsfoweAbp

Info.plist

@@ -13,9 +13,9 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.3.0</string>
+	<string>0.3.1</string>
 	<key>CFBundleVersion</key>
-	<string>3</string>
+	<string>4</string>
 	<key>LSMinimumSystemVersion</key>
 	<string>14.0</string>
 	<key>LSUIElement</key>

Package.swift

@@ -27,5 +27,14 @@ let package = Package(
             dependencies: ["ShotdeckCore"],
             swiftSettings: [.swiftLanguageMode(.v6)]
         ),
+        // Exercises the real Shotdeck-app-target wiring (AppDelegate.makeLaunchModel(),
+        // AppModel.bootstrap()) via @testable import — logic ShotdeckCoreTests cannot
+        // reach because it only depends on ShotdeckCore, not the Shotdeck executable
+        // target itself. See ReturnWatcherLaunchWiringTests.swift.
+        .testTarget(
+            name: "ShotdeckTests",
+            dependencies: ["Shotdeck", "ShotdeckCore"],
+            swiftSettings: [.swiftLanguageMode(.v6)]
+        ),
     ]
 )

Sources/Shotdeck/AppModel.swift

@@ -28,10 +28,19 @@ public final class AppModel {
     public private(set) var allReturns: [ReturnedDocument] = []
     public private(set) var commentedReturns: [ReturnedDocument] = []
     public private(set) var statusLine: String?
+    public private(set) var updateStatus: 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 transport choice; WP-onedrive reads this to pick the send path and to drive
+    /// the Settings "Send via" picker and the menu's "Send…" label.
+    public private(set) var transport: SendTransport
+    /// Ground truth for the Settings OneDrive row: nil means "no OneDrive folder found".
+    /// Views read this instead of calling `OneDriveLocator.resolveOneDriveFolder()`
+    /// directly, so state (and testing with a fake home) flows through the model like
+    /// everything else — never a View reaching past the model for real UserDefaults/home.
+    public private(set) var resolvedOneDriveFolder: URL?
     /// 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`.
@@ -83,20 +92,22 @@ public final class AppModel {
         )
         self.region = Self.loadPersistedRegion()
         self.screenRecordingGranted = ScreenCapturer.isScreenRecordingGranted
-        // Seeded from FolderSettings.resolve() via resolvedAppSupportPaths — never .standard().
-        let folders = FolderSettings.resolve()
+        // Seeded from TransportSettings.effectiveFolders() — the one place that combines
+        // the transport choice with FolderSettings/OneDriveLocator. Never call
+        // FolderSettings.resolve() directly outside that function.
+        let folders = TransportSettings.effectiveFolders()
         self.outboxURL = folders.outbox
         self.watchFolderURL = folders.watch
         self.outboxDisplayName = folders.outbox.lastPathComponent
         self.watchFolderDisplayName = folders.watch.lastPathComponent
+        self.transport = folders.transport
+        self.resolvedOneDriveFolder = OneDriveLocator.resolveOneDriveFolder()
         self.captureHotkey = HotkeyPreference.load()
         self.updateChecker = UpdateChecker()
         self.updateChecker.onChecked = { [weak self] in
             guard let self else { return }
             self.updateAvailable = self.updateChecker.availableUpdate
-            if let message = self.updateChecker.statusMessage {
-                self.setStatus(message)
-            }
+            self.setUpdateStatus(self.updateChecker.statusMessage)
         }
         self.updateChecker.onCheckingChanged = { [weak self] checking in
             self?.isCheckingForUpdates = checking
@@ -107,13 +118,13 @@ public final class AppModel {
     public var appVersion: String { UpdateChecker.currentVersion() }
     /// Version recorded in the app-managed rollback copy, when one exists.
     public var previousVersion: String? { updateChecker.previousVersion() }
-    /// Most recent status text — shared with the general status line by design
-    /// (Redline has one status channel, not a separate update-only one).
-    public var updateStatusMessage: String? { statusLine }
+    /// Update-related status text (checked time, staged update, errors). Displayed only in the footer.
+    public var updateStatusMessage: String? { updateStatus }
 
     // MARK: Seam mutators — the only way a WP-4b/4c extension changes state.
 
     func setStatus(_ text: String?) { statusLine = text }
+    func setUpdateStatus(_ text: String?) { updateStatus = text }
     func setSending(_ value: Bool) { isSending = value }
     func setCapturing(_ value: Bool) { isCapturing = value }
     func replaceSession(_ new: CaptureSession) { session = new }
@@ -131,6 +142,23 @@ public final class AppModel {
         watchFolderURL = watch
         setFolderDisplayNames(outbox: outbox.lastPathComponent, watch: watch.lastPathComponent)
     }
+    func setTransport(_ value: SendTransport) { transport = value }
+    func setResolvedOneDriveFolder(_ value: URL?) { resolvedOneDriveFolder = value }
+
+    /// Bumped by chooseTransport/chooseOneDriveFolder (SettingsView.swift) before each
+    /// spawns its async watcher-reconcile Task; that Task checks its own snapshot
+    /// against the live value before every mutating step, so rapid toggling always
+    /// lets the LAST choice win instead of applying stale, superseded work. Not
+    /// `@Observable`-relevant state — pure internal bookkeeping, never read by a View.
+    var reconcileGeneration = 0
+    /// The MOST RECENT watcher-reconcile Task spawned by chooseTransport/
+    /// chooseOneDriveFolder, if one is still (or was just) in flight. send() awaits
+    /// this BEFORE snapshotting transport/folder, so a toggle immediately followed by
+    /// Send can never race ahead of the reconcile it depends on (the watcher's
+    /// recordUncommented flag briefly lagging the just-chosen transport, for example).
+    /// `Task<Void, Never>` never throws; awaiting an already-completed task's `.value`
+    /// returns immediately. Not `@Observable`-relevant — pure internal bookkeeping.
+    var pendingReconcileTask: Task<Void, Never>?
     func rememberLastComposedPDF(_ url: URL) { lastComposedPDFURL = url }
 
     /// True when a last-composed PDF path is known this run, or the newest
@@ -198,7 +226,29 @@ public final class AppModel {
             // Empty ledger on first run is not an error.
         }
 
+        // OneDrive mode: outbox == watch folder, so a freshly written, unmarked PDF must
+        // never show up as a return; only a document that already carries a mark does.
+        // Also make sure the resolved OneDrive folder actually exists before the
+        // watcher starts watching it (bootstrap is the other creation trigger besides
+        // chooseTransport/chooseOneDriveFolder — see TransportSettings.effectiveFolders).
+        if transport == .oneDrive {
+            try? FileManager.default.createDirectory(at: outboxURL, withIntermediateDirectories: true)
+        }
+        setResolvedOneDriveFolder(OneDriveLocator.resolveOneDriveFolder())
+        await watcher.setRecordUncommented(transport == .airDrop)
+
         do {
+            // BLOCKER fix: reconcile the watcher's internal watchFolder with the live
+            // watchFolderURL UNCONDITIONALLY, before it ever starts. `paths` (and so the
+            // watcher's initial folder, set in its own init) now comes from the same
+            // transport-aware TransportSettings.effectiveFolders() as watchFolderURL, so
+            // in the normal case this is a no-op — but it is the only thing that would
+            // have caught the old bug (launch paths built AirDrop-only while OneDrive was
+            // the persisted transport, leaving the watcher's FSEvents stream pointed at a
+            // stale folder for the whole session) and it stays cheap insurance against
+            // that class of drift ever recurring. Calling it before start() only updates
+            // the stored folder — no FSEvents stream exists yet to restart.
+            try await watcher.updateWatchFolder(watchFolderURL)
             try await watcher.start { [weak self] _ in
                 Task { @MainActor in
                     guard let self else { return }
@@ -211,17 +261,29 @@ public final class AppModel {
             setStatus((error as? ShotdeckError)?.errorDescription ?? "Could not watch the return folder.")
         }
 
-        let pref = HotkeyPreference.load()
-        captureHotkey = pref
-        if !bindCaptureHotkey(pref) {
-            setStatus("\(pref.displayString) is already used by another app — capture only works from the menu.")
-        }
-
-        let skipSchedule =
+        // Env-var-flagged self-test/headless runs (PickerSelfTest's phases, PanelSnapshot,
+        // and the new ShotdeckTests launch-wiring regression test) skip two real-world
+        // side effects that are unsafe or meaningless in that context: the update-check
+        // schedule (a real network call), and binding the REAL, process-wide Carbon
+        // global hotkey — which is not safe to exercise in an automated/parallel test
+        // process (it can collide with ShotdeckCoreTests' own HotkeyCenterCarbonTests
+        // running in the same test binary) and was never meaningfully exercised by any
+        // self-test anyway. A real user launch never sets these env vars, so production
+        // behavior is unchanged.
+        let isSelfTestRun =
             ProcessInfo.processInfo.environment["SHOTDECK_PICKER_SELFTEST"] != nil
             || ProcessInfo.processInfo.environment["SHOTDECK_SNAPSHOT_DIR"] != nil
             || ProcessInfo.processInfo.environment["SHOTDECK_UPDATE_SELFTEST"] != nil
-        if !skipSchedule {
+            || ProcessInfo.processInfo.environment["SHOTDECK_ONEDRIVE_SELFTEST"] != nil
+            || ProcessInfo.processInfo.environment["REDLINE_SELFTEST_PHASE"] != nil
+
+        let pref = HotkeyPreference.load()
+        captureHotkey = pref
+        if !isSelfTestRun, !bindCaptureHotkey(pref) {
+            setStatus("\(pref.displayString) is already used by another app — capture only works from the menu.")
+        }
+
+        if !isSelfTestRun {
             updateChecker.startSchedule()
         }
     }

Sources/Shotdeck/MenuBarView.swift

@@ -108,7 +108,7 @@ struct MenuBarView: View {
                     model.setStatus("Send is not available in this build.")
                 }
             } label: {
-                actionLabel("Send…")
+                actionLabel(model.transport == .oneDrive ? "Send to OneDrive" : "Send…")
             }
             .disabled(model.session.isEmpty || model.isSending)
 

Sources/Shotdeck/PanelSnapshot.swift

@@ -61,6 +61,28 @@ enum PanelSnapshot {
         try renderMenuBar(model: model, to: directory, name: "03-empty-session")
 
         // 04 — three real PNGs in the temp spool so SessionStrip thumbnails decode.
+        try await addSampleCaptures(to: model)
+        try renderMenuBar(model: model, to: directory, name: "04-captures-present")
+
+        // 05 — two inspected PDFs in the temp ledger, one marked / one not.
+        try await seedReturns(model: model)
+        try renderMenuBar(model: model, to: directory, name: "05-returns-present")
+
+        // 06 — SettingsView against the same isolated model.
+        try render(
+            SettingsView().environment(model),
+            to: directory.appendingPathComponent("panel-06-settings.png")
+        )
+
+        // 07/08/09 — OneDrive-mode Settings + menu bar, on a SEPARATE isolated model so
+        // this transport switch never bleeds into the AirDrop-mode panels above.
+        try await captureOneDrivePanels(to: directory)
+    }
+
+    /// Three real PNGs appended to the given model's temp spool so SessionStrip
+    /// thumbnails decode. Shared by panel 04 (AirDrop) and panel 09 (OneDrive).
+    @MainActor
+    private static func addSampleCaptures(to model: AppModel) async throws {
         let swatches: [(CGFloat, CGFloat, CGFloat)] = [
             (0.85, 0.22, 0.18),
             (0.18, 0.62, 0.32),
@@ -77,17 +99,93 @@ enum PanelSnapshot {
             )
         }
         model.replaceSession(try await model.spool.currentSession())
-        try renderMenuBar(model: model, to: directory, name: "04-captures-present")
+    }
 
-        // 05 — two inspected PDFs in the temp ledger, one marked / one not.
-        try await seedReturns(model: model)
-        try renderMenuBar(model: model, to: directory, name: "05-returns-present")
+    /// Panels 07-09: OneDrive transport, on its own isolated model/temp root so
+    /// switching transport here never touches the AirDrop-mode model above, the real
+    /// home directory, or UserDefaults.standard. The "resolved" and "not found" states
+    /// are produced by calling the real OneDriveLocator functions against fake home
+    /// trees built under this snapshot's own temp root — never a hand-typed path.
+    @MainActor
+    private static func captureOneDrivePanels(to directory: URL) async throws {
+        let (model, root) = try makeIsolatedModel()
+        defer { try? FileManager.default.removeItem(at: root) }
+        model.setTransport(.oneDrive)
 
-        // 06 — SettingsView against the same isolated model.
+        // 07 — a resolved OneDrive folder, shaped like the real default
+        // (…/Library/CloudStorage/OneDrive-MMDGROUP/Redline): a fake home tree with a
+        // real OneDrive-MMDGROUP directory under it, resolved via the same pure
+        // OneDriveLocator function production code uses — never a hand-typed path.
+        let fakeHomeWithOneDrive = root.appendingPathComponent("fake-home-with-onedrive", isDirectory: true)
+        let syncRoot = fakeHomeWithOneDrive
+            .appendingPathComponent("Library/CloudStorage/OneDrive-MMDGROUP", isDirectory: true)
+        try FileManager.default.createDirectory(at: syncRoot, withIntermediateDirectories: true)
+        guard let resolvedFolder = OneDriveLocator.defaultRedlineFolder(
+            home: fakeHomeWithOneDrive, fileManager: .default
+        ) else {
+            throw SnapshotError.oneDriveFixtureFailed("fake OneDrive-MMDGROUP root did not resolve")
+        }
+        model.setResolvedOneDriveFolder(resolvedFolder)
         try render(
             SettingsView().environment(model),
-            to: directory.appendingPathComponent("panel-06-settings.png")
+            to: directory.appendingPathComponent("panel-07-settings-onedrive.png")
         )
+
+        // 08 — no OneDrive folder found: a fake home with NO Library/CloudStorage at
+        // all, and a throwaway UserDefaults suite (never .standard, never touched
+        // before) so the stored-override check also legitimately finds nothing.
+        let fakeHomeWithoutOneDrive = root.appendingPathComponent("fake-home-without-onedrive", isDirectory: true)
+        try FileManager.default.createDirectory(at: fakeHomeWithoutOneDrive, withIntermediateDirectories: true)
+        let isolatedDefaults = try makeIsolatedDefaultsSuite()
+        defer { isolatedDefaults.defaults.removePersistentDomain(forName: isolatedDefaults.suiteName) }
+        let missingFolder = OneDriveLocator.resolveOneDriveFolder(
+            defaults: isolatedDefaults.defaults, home: fakeHomeWithoutOneDrive, fileManager: .default
+        )
+        guard missingFolder == nil else {
+            throw SnapshotError.oneDriveFixtureFailed("fake home without OneDrive unexpectedly resolved")
+        }
+        model.setResolvedOneDriveFolder(nil)
+        try render(
+            SettingsView().environment(model),
+            to: directory.appendingPathComponent("panel-08-settings-onedrive-missing.png")
+        )
+
+        // 09 — menu bar panel, 3 captures present, OneDrive mode ("Send to OneDrive").
+        model.snapshotSetScreenRecordingGranted(true)
+        model.replaceRegion(sampleRegion())
+        try await addSampleCaptures(to: model)
+        try renderMenuBar(model: model, to: directory, name: "09-captures-present-onedrive")
+
+        // 10 — update idle: 3 captures, no update available, footer "Redline <ver>", row "Check for updates".
+        let (updateModel, updateRoot) = try makeIsolatedModel()
+        defer { try? FileManager.default.removeItem(at: updateRoot) }
+        updateModel.snapshotSetScreenRecordingGranted(true)
+        updateModel.replaceRegion(sampleRegion())
+        try await addSampleCaptures(to: updateModel)
+        // No update set, updateChecker in idle state, no previous version
+        updateModel.snapshotSetPreviousVersion(nil)
+        try renderMenuBar(model: updateModel, to: directory, name: "10-update-idle")
+
+        // 11 — update checking: same as 10 but isCheckingForUpdates = true.
+        updateModel.snapshotSetIsCheckingForUpdates(true)
+        try renderMenuBar(model: updateModel, to: directory, name: "11-update-checking")
+        updateModel.snapshotSetIsCheckingForUpdates(false)
+
+        // 12 — update up-to-date: footer status line reads "Redline <ver> is up to date, checked 10:42 Dubai".
+        let upToDateMessage = "Redline \(updateModel.appVersion) is up to date, checked 10:42 Dubai"
+        updateModel.snapshotSetUpdateStatusMessage(upToDateMessage)
+        try renderMenuBar(model: updateModel, to: directory, name: "12-update-uptodate")
+
+        // 13 — update staged: row "Update to 9.9.9" present, footer status "Update to 9.9.9 is ready".
+        updateModel.snapshotSetUpdateAvailable(version: "9.9.9", notes: "Test release")
+        updateModel.snapshotSetUpdateStatusMessage("Update to 9.9.9 is ready")
+        try renderMenuBar(model: updateModel, to: directory, name: "13-update-staged")
+
+        // 14 — update revert: row "Revert to 0.2.0" present.
+        updateModel.snapshotSetUpdateAvailable(version: nil, notes: nil)  // Clear the staged update
+        updateModel.snapshotSetUpdateStatusMessage(nil)
+        updateModel.snapshotSetPreviousVersion("0.2.0")
+        try renderMenuBar(model: updateModel, to: directory, name: "14-update-revert")
     }
 
     @MainActor
@@ -177,6 +275,23 @@ enum PanelSnapshot {
         return (model, root)
     }
 
+    /// A throwaway UserDefaults suite — never `.standard` — for the panel-08 fixture,
+    /// the same isolation pattern ShotdeckCoreTests uses for TransportSettings/
+    /// OneDriveLocator tests.
+    private struct IsolatedDefaultsSuite {
+        let suiteName: String
+        let defaults: UserDefaults
+    }
+
+    private static func makeIsolatedDefaultsSuite() throws -> IsolatedDefaultsSuite {
+        let suiteName = "shotdeck-panel-snapshot-\(UUID().uuidString)"
+        guard let defaults = UserDefaults(suiteName: suiteName) else {
+            throw SnapshotError.oneDriveFixtureFailed("could not create isolated UserDefaults suite")
+        }
+        defaults.removePersistentDomain(forName: suiteName)
+        return IsolatedDefaultsSuite(suiteName: suiteName, defaults: defaults)
+    }
+
     @MainActor
     private static func seedReturns(model: AppModel) async throws {
         let watch = model.paths.watchFolder
@@ -276,6 +391,40 @@ extension AppModel {
         )
         self[keyPath: writable] = granted
     }
+
+    /// Snapshot-only: set isCheckingForUpdates without triggering a real check.
+    func snapshotSetIsCheckingForUpdates(_ checking: Bool) {
+        let writable: ReferenceWritableKeyPath<AppModel, Bool> = unsafeBitCast(
+            \AppModel.isCheckingForUpdates, to: ReferenceWritableKeyPath<AppModel, Bool>.self
+        )
+        self[keyPath: writable] = checking
+    }
+
+    /// Snapshot-only: set updateStatusMessage for panel display.
+    func snapshotSetUpdateStatusMessage(_ message: String?) {
+        setUpdateStatus(message)
+    }
+
+    /// Snapshot-only: set updateAvailable without triggering a real download.
+    func snapshotSetUpdateAvailable(version: String?, notes: String?) {
+        if let version = version, let notes = notes {
+            let writable: ReferenceWritableKeyPath<AppModel, (version: String, notes: String)?> = unsafeBitCast(
+                \AppModel.updateAvailable, to: ReferenceWritableKeyPath<AppModel, (version: String, notes: String)?>.self
+            )
+            self[keyPath: writable] = (version: version, notes: notes)
+        } else {
+            let writable: ReferenceWritableKeyPath<AppModel, (version: String, notes: String)?> = unsafeBitCast(
+                \AppModel.updateAvailable, to: ReferenceWritableKeyPath<AppModel, (version: String, notes: String)?>.self
+            )
+            self[keyPath: writable] = nil
+        }
+    }
+
+    /// Snapshot-only: set a fake previousVersion for the revert panel.
+    func snapshotSetPreviousVersion(_ version: String?) {
+        updateChecker.snapshotPreviousVersionOverride = version
+        updateChecker.snapshotUsesPreviousVersionOverride = true
+    }
 }
 
 private enum SnapshotError: Error, CustomStringConvertible {
@@ -283,6 +432,7 @@ private enum SnapshotError: Error, CustomStringConvertible {
     case encodeFailed(String)
     case pngGenerationFailed
     case pdfWriteFailed(String)
+    case oneDriveFixtureFailed(String)
 
     var description: String {
         switch self {
@@ -290,6 +440,7 @@ private enum SnapshotError: Error, CustomStringConvertible {
         case .encodeFailed(let name): return "PNG encode failed for \(name)"
         case .pngGenerationFailed: return "CoreGraphics PNG generation failed"
         case .pdfWriteFailed(let name): return "could not write \(name)"
+        case .oneDriveFixtureFailed(let detail): return "OneDrive snapshot fixture failed: \(detail)"
         }
     }
 }

Sources/Shotdeck/PickerSelfTest.swift

@@ -3,6 +3,7 @@ import CoreGraphics
 import Darwin
 import Foundation
 import ImageIO
+import PDFKit
 import ShotdeckCore
 
 /// In-process self-test for the region picker, driven by `SHOTDECK_PICKER_SELFTEST`.
@@ -173,7 +174,7 @@ enum PickerSelfTest {
                 try await executeSendTruth()
                 print("SEND-TRUTH PASS")
                 fflush(stdout)
-                if !startUpdateSelfTestIfRequested() {
+                if !startUpdateSelfTestIfRequested(), !startOneDriveSelfTestIfRequested() {
                     exit(0)
                 }
             } catch {
@@ -222,7 +223,7 @@ enum PickerSelfTest {
             sendTruthFail("seeded session was empty")
         }
 
-        let pending = try await model.composePDFForSend()
+        let pending = try await model.composePDFForSend(outbox: model.outboxURL, transport: .airDrop)
         guard fm.fileExists(atPath: pending.fileURL.path) else {
             sendTruthFail("PDF was not written")
         }
@@ -315,7 +316,9 @@ enum PickerSelfTest {
                 try await runUpdateSelfTest(outputDirectory: output)
                 print("UPDATE-SELFTEST PASS version=99.0.0")
                 fflush(stdout)
-                exit(0)
+                if !startOneDriveSelfTestIfRequested() {
+                    exit(0)
+                }
             } catch let error as UpdateSelfTestError {
                 updateFail(error.description)
             } catch {
@@ -573,6 +576,335 @@ enum PickerSelfTest {
         exit(1)
     }
 
+    /// Phase 5: proves the OneDrive transport end to end against a REAL sync root —
+    /// resolved at runtime via `OneDriveLocator.syncRoots()`, never a hardcoded path, so
+    /// this runs correctly on any Mac/account that has OneDrive signed in (MMD-named
+    /// root preferred, same as production). Triggered by `SHOTDECK_ONEDRIVE_SELFTEST`
+    /// when chained after PICKER/SEND-TRUTH/UPDATE-SELFTEST — the exact pattern
+    /// `startUpdateSelfTestIfRequested` uses for its own env var. Returns true when the
+    /// async phase was scheduled (it calls `exit` itself).
+    @discardableResult
+    private static func startOneDriveSelfTestIfRequested() -> Bool {
+        guard ProcessInfo.processInfo.environment["SHOTDECK_ONEDRIVE_SELFTEST"] != nil else {
+            return false
+        }
+        runOneDriveSelfTestAndExit()
+        return true
+    }
+
+    /// Entry point for running ONLY this phase, bypassing the on-screen picker chain
+    /// entirely. The harness has no other per-phase selector, so this is the escape
+    /// hatch: `REDLINE_SELFTEST_PHASE=onedrive`.
+    static func runOneDriveOnlyIfRequested() {
+        guard ProcessInfo.processInfo.environment["REDLINE_SELFTEST_PHASE"] == "onedrive" else {
+            return
+        }
+        // Same hop as runIfRequested(): a plain main-queue turn after NSApp starts, so
+        // AppKit/PDFKit calls inside the phase are not racing app launch.
+        DispatchQueue.main.async {
+            MainActor.assumeIsolated {
+                runOneDriveSelfTestAndExit()
+            }
+        }
+    }
+
+    private static func runOneDriveSelfTestAndExit() {
+        // Never a false PASS: no real OneDrive sync root on this machine/account is a
+        // SKIP (still non-zero exit), not silently treated as passing.
+        guard let syncRoot = OneDriveLocator.syncRoots().first else {
+            print("ONEDRIVE-SELFTEST SKIP no OneDrive sync root")
+            fflush(stdout)
+            exit(1)
+        }
+        Task { @MainActor in
+            do {
+                let folder = try await executeOneDriveSelfTest(syncRoot: syncRoot)
+                print("ONEDRIVE-SELFTEST PASS path=\(folder.path)")
+                fflush(stdout)
+                exit(0)
+            } catch let error as OneDriveSelfTestError {
+                oneDriveFail(error.description)
+            } catch {
+                oneDriveFail(String(describing: error))
+            }
+        }
+    }
+
+    /// Sub-step 1: builds a session, sends it through the OneDrive branch of
+    /// `send(anchor: nil)` against a NEW folder under `syncRoot`, confirms the watcher
+    /// does NOT report the freshly-written unmarked PDF as a return, then adds a real
+    /// PDFKit ink annotation in place (what the iPad does) and confirms the watcher now
+    /// reports it as commented.
+    ///
+    /// Sub-step 1b: rapid transport toggling (chooseTransport(.airDrop) immediately
+    /// followed by chooseTransport(.oneDrive), no await between them) must still end
+    /// with the watcher pointed at the OneDrive folder — proves the generation-guarded
+    /// reconcile in chooseTransport/chooseOneDriveFolder (SettingsView.swift) really
+    /// does let the last choice win instead of an earlier, superseded call applying its
+    /// stale folder after a later one already won.
+    ///
+    /// Sub-step 1c: the OTHER race — a toggle immediately followed by Send, with no
+    /// sleep at all before send() runs. Proves send() awaits `pendingReconcileTask`
+    /// before snapshotting transport/folder: a freshly-sent, still-unmarked PDF must
+    /// never be reported as an already-returned document (which is exactly what would
+    /// happen if send() raced ahead while recordUncommented was still `true`, stale
+    /// from the .airDrop leg of the toggle).
+    ///
+    /// Sub-step 2: relaunch simulation — the exact BLOCKER scenario this phase exists to
+    /// catch. OneDrive is still persisted in defaults from sub-step 1; builds a FRESH
+    /// model the same way the real app launches (`AppDelegate.makeLaunchModel()` itself,
+    /// not a reimplementation), bootstraps it, then marks a PDF in the folder in place —
+    /// the relaunched watcher must report it. A temp app-support root keeps this off the
+    /// real ~/Library/Application Support/Shotdeck.
+    ///
+    /// Never deletes anything under OneDrive — the created folder and PDFs are left in
+    /// place for Ben to inspect / for the real iPad round trip.
+    private static func executeOneDriveSelfTest(syncRoot: URL) async throws -> URL {
+        let fm = FileManager.default
+
+        // UserDefaults.standard is the ONLY defaults instance send()/TransportSettings
+        // actually read at runtime (there is no defaults-threading through AppModel), so
+        // "isolated" here means snapshot-and-restore around the real keys — the same
+        // pattern runRegionPersistPhase already uses for CaptureRegion.defaultsKey.
+        let defaults = UserDefaults.standard
+        let previousTransport = defaults.string(forKey: TransportSettings.transportDefaultsKey)
+        let previousFolder = defaults.string(forKey: TransportSettings.oneDriveFolderDefaultsKey)
+        defer {
+            if let previousTransport {
+                defaults.set(previousTransport, forKey: TransportSettings.transportDefaultsKey)
+            } else {
+                defaults.removeObject(forKey: TransportSettings.transportDefaultsKey)
+            }
+            if let previousFolder {
+                defaults.set(previousFolder, forKey: TransportSettings.oneDriveFolderDefaultsKey)
+            } else {
+                defaults.removeObject(forKey: TransportSettings.oneDriveFolderDefaultsKey)
+            }
+        }
+
+        let stamp = DubaiTime.fileStamp(Date())
+        let selftestFolder = syncRoot.appendingPathComponent("Redline-selftest-\(stamp)", isDirectory: true)
+        try fm.createDirectory(at: selftestFolder, withIntermediateDirectories: true)
+
+        TransportSettings.setTransport(.oneDrive, defaults: defaults)
+        TransportSettings.setOneDriveFolder(selftestFolder, defaults: defaults)
+
+        // Local spool root only — the outbox/watch folder is the real OneDrive folder.
+        let spoolRoot = fm.temporaryDirectory
+            .appendingPathComponent("shotdeck-onedrive-selftest-\(UUID().uuidString)", isDirectory: true)
+        defer { try? fm.removeItem(at: spoolRoot) }
+
+        let paths = try AppSupportPaths(root: spoolRoot, outbox: selftestFolder, watchFolder: selftestFolder)
+        let ledger = try ReturnLedger(paths: paths)
+        let watcher = ReturnWatcher(paths: paths, ledger: ledger)
+        await watcher.setRecordUncommented(false)   // OneDrive mode: today's default is AirDrop's `true`.
+
+        let model = AppModel(
+            paths: paths,
+            spool: try SpoolStore(paths: paths),
+            composer: PDFComposer(),
+            capturer: ScreenCapturer(),
+            hotkeys: HotkeyCenter(),
+            picker: RegionPickerController(),
+            ledger: ledger,
+            watcher: watcher
+        )
+        model.setFolderURLs(outbox: selftestFolder, watch: selftestFolder)
+        model.setTransport(.oneDrive)
+
+        let png = try makeTinyPNGData()
+        _ = try await model.spool.append(
+            pngData: png, pixelWidth: 64, pixelHeight: 48, scale: 1, capturedAt: Date()
+        )
+        model.replaceSession(try await model.spool.currentSession())
+        guard !model.session.isEmpty else {
+            throw OneDriveSelfTestError.detail("seeded session was empty")
+        }
+
+        await model.send(anchor: nil)
+
+        guard let status = model.statusLine, status.hasPrefix("Saved to OneDrive") else {
+            throw OneDriveSelfTestError.detail(
+                "status did not start with 'Saved to OneDrive': \(model.statusLine ?? "nil")"
+            )
+        }
+        guard model.session.isEmpty else {
+            throw OneDriveSelfTestError.detail("session was not archived after the OneDrive send")
+        }
+
+        let written = (try? fm.contentsOfDirectory(at: selftestFolder, includingPropertiesForKeys: nil)) ?? []
+        guard let pdfURL = written.first(where: { $0.pathExtension.lowercased() == "pdf" }) else {
+            throw OneDriveSelfTestError.detail("no PDF found in \(selftestFolder.path)")
+        }
+
+        // Unmarked so far: the watcher must not treat it as a return.
+        let beforeMarkup = try await watcher.scanNow()
+        guard !beforeMarkup.contains(where: { $0.fileURL == pdfURL }) else {
+            throw OneDriveSelfTestError.detail("unmarked PDF was reported as returned by scanNow")
+        }
+        let commentedBefore = try await ledger.commented()
+        guard !commentedBefore.contains(where: { $0.fileURL == pdfURL }) else {
+            throw OneDriveSelfTestError.detail("unmarked PDF was recorded as commented in the ledger")
+        }
+
+        // What the iPad does: mark it up in place with a real ink annotation, then save.
+        try addInkMark(to: pdfURL)
+
+        let afterMarkup = try await watcher.scanNow()
+        guard let recorded = afterMarkup.first(where: { $0.fileURL == pdfURL }), recorded.isCommented else {
+            throw OneDriveSelfTestError.detail("annotated PDF was not reported as commented by scanNow")
+        }
+        let commentedAfter = try await ledger.commented()
+        guard commentedAfter.contains(where: { $0.fileURL == pdfURL }) else {
+            throw OneDriveSelfTestError.detail("annotated PDF was not recorded in the ledger as commented")
+        }
+
+        // Sub-step 1b: rapid toggle race — see the doc comment above this function.
+        model.chooseTransport(.airDrop)
+        model.chooseTransport(.oneDrive)   // immediately superseding the call above
+        // The generation guard itself is what's under test, not this wait — it just
+        // gives the (already-guarded) reconcile Task a moment to settle either way.
+        try await Task.sleep(for: .milliseconds(500))
+        guard model.transport == .oneDrive else {
+            throw OneDriveSelfTestError.detail(
+                "rapid toggle: model.transport ended as \(model.transport), expected .oneDrive"
+            )
+        }
+        let racePDFURL = selftestFolder.appendingPathComponent("Redline-race-\(stamp).pdf")
+        try writeUnmarkedRedlinePDF(to: racePDFURL)
+        try addInkMark(to: racePDFURL)
+        let raceFound = try await model.watcher.scanNow()
+        guard raceFound.first(where: { $0.fileURL == racePDFURL })?.isCommented == true else {
+            throw OneDriveSelfTestError.detail(
+                "rapid toggle: watcher did not end up watching \(selftestFolder.path) — an earlier, superseded chooseTransport call won"
+            )
+        }
+
+        // Sub-step 1c: toggle-then-immediate-send race — see the doc comment above
+        // this function. No sleep here: this IS the exact race window finding #3
+        // exists to close, so send() itself must wait out the pending reconcile.
+        let racePNG = try makeTinyPNGData()
+        _ = try await model.spool.append(
+            pngData: racePNG, pixelWidth: 64, pixelHeight: 48, scale: 1, capturedAt: Date()
+        )
+        model.replaceSession(try await model.spool.currentSession())
+        guard !model.session.isEmpty else {
+            throw OneDriveSelfTestError.detail("toggle-then-send: re-seeded session was empty")
+        }
+
+        let knownBeforeToggleSend = Set(
+            ((try? fm.contentsOfDirectory(at: selftestFolder, includingPropertiesForKeys: nil)) ?? [])
+                .map(\.lastPathComponent)
+        )
+        model.chooseTransport(.airDrop)
+        model.chooseTransport(.oneDrive)   // immediately superseding, no sleep before send()
+        await model.send(anchor: nil)
+
+        guard let toggleSendStatus = model.statusLine, toggleSendStatus.hasPrefix("Saved to OneDrive") else {
+            throw OneDriveSelfTestError.detail(
+                "toggle-then-send: status was \(model.statusLine ?? "nil"), expected 'Saved to OneDrive'"
+            )
+        }
+        guard model.session.isEmpty else {
+            throw OneDriveSelfTestError.detail("toggle-then-send: session was not archived")
+        }
+        let filesAfterToggleSend = (try? fm.contentsOfDirectory(
+            at: selftestFolder, includingPropertiesForKeys: nil
+        )) ?? []
+        guard let toggleSendPDFURL = filesAfterToggleSend.first(where: {
+            $0.pathExtension.lowercased() == "pdf" && !knownBeforeToggleSend.contains($0.lastPathComponent)
+        }) else {
+            throw OneDriveSelfTestError.detail("toggle-then-send: no new PDF found in \(selftestFolder.path)")
+        }
+        // The freshly-sent PDF is UNMARKED. If send() had raced ahead of the pending
+        // reconcile, recordUncommented could still have been (stale) true, and this
+        // scan would wrongly report it as already returned.
+        let scanAfterToggleSend = try await model.watcher.scanNow()
+        guard !scanAfterToggleSend.contains(where: { $0.fileURL == toggleSendPDFURL }) else {
+            throw OneDriveSelfTestError.detail(
+                "toggle-then-send: freshly-sent unmarked PDF at \(toggleSendPDFURL.path) was reported as returned — send() raced ahead of the pending reconcile"
+            )
+        }
+
+        // Sub-step 2: relaunch simulation — see the doc comment above this function.
+        let relaunchAppSupportRoot = fm.temporaryDirectory
+            .appendingPathComponent("shotdeck-onedrive-relaunch-\(UUID().uuidString)", isDirectory: true)
+        defer { try? fm.removeItem(at: relaunchAppSupportRoot) }
+
+        let relaunchModel = AppDelegate.makeLaunchModel(appSupportRoot: relaunchAppSupportRoot)
+        guard relaunchModel.transport == .oneDrive else {
+            throw OneDriveSelfTestError.detail(
+                "relaunch: model transport was \(relaunchModel.transport), expected .oneDrive"
+            )
+        }
+        guard relaunchModel.watchFolderURL.path == selftestFolder.path else {
+            throw OneDriveSelfTestError.detail(
+                "relaunch: model watchFolderURL was \(relaunchModel.watchFolderURL.path), expected \(selftestFolder.path) — this is the exact BLOCKER this phase guards against"
+            )
+        }
+
+        await relaunchModel.bootstrap()
+
+        let relaunchPDFURL = selftestFolder.appendingPathComponent("Redline-relaunch-\(stamp).pdf")
+        try writeUnmarkedRedlinePDF(to: relaunchPDFURL)
+        try addInkMark(to: relaunchPDFURL)
+
+        let relaunchFound = try await relaunchModel.watcher.scanNow()
+        guard relaunchFound.first(where: { $0.fileURL == relaunchPDFURL })?.isCommented == true else {
+            throw OneDriveSelfTestError.detail(
+                "relaunch: watcher did not report the marked PDF at \(relaunchPDFURL.path) as returned — it was watching the wrong folder after relaunch"
+            )
+        }
+        await relaunchModel.watcher.stop()
+
+        return selftestFolder
+    }
+
+    /// Adds a real PDFKit ink annotation to the PDF at `url` in place and saves it —
+    /// exactly what the iPad does when marking up a page.
+    private static func addInkMark(to url: URL) throws {
+        guard let document = PDFDocument(url: url), let page = document.page(at: 0) else {
+            throw OneDriveSelfTestError.detail("could not reopen \(url.path) to annotate it")
+        }
+        let ink = PDFAnnotation(
+            bounds: CGRect(x: 20, y: 20, width: 60, height: 60),
+            forType: .ink,
+            withProperties: nil
+        )
+        let stroke = NSBezierPath()
+        stroke.move(to: NSPoint(x: 20, y: 20))
+        stroke.line(to: NSPoint(x: 80, y: 80))
+        ink.add(stroke)
+        page.addAnnotation(ink)
+        guard document.write(to: url) else {
+            throw OneDriveSelfTestError.detail("could not save the annotated PDF back to \(url.path)")
+        }
+    }
+
+    /// Writes a fresh, unmarked, single-page "Redline"-creator PDF straight to `url` —
+    /// standing in for a PDF that has just landed in the watch folder, before any
+    /// human mark. Used by the rapid-toggle and relaunch sub-steps, which don't need to
+    /// exercise send()/composePDFForSend() again (sub-step 1 already does).
+    private static func writeUnmarkedRedlinePDF(to url: URL) throws {
+        let document = PDFDocument()
+        let page = PDFPage()
+        page.setBounds(CGRect(x: 0, y: 0, width: 612, height: 792), for: .mediaBox)
+        document.insert(page, at: 0)
+        document.documentAttributes = [
+            PDFDocumentAttribute.creatorAttribute: "Redline",
+            PDFDocumentAttribute.subjectAttribute: UUID().uuidString,
+        ]
+        guard document.write(to: url) else {
+            throw OneDriveSelfTestError.detail("could not write \(url.path)")
+        }
+    }
+
+    private static func oneDriveFail(_ detail: String) -> Never {
+        print("ONEDRIVE-SELFTEST FAIL \(detail)")
+        fflush(stdout)
+        exit(1)
+    }
+
     private static func interpolate(_ step: Int) -> NSPoint {
         let t = CGFloat(step) / CGFloat(dragSteps)
         return NSPoint(
@@ -638,3 +970,12 @@ private enum UpdateSelfTestError: Error, CustomStringConvertible {
         }
     }
 }
+
+private enum OneDriveSelfTestError: Error, CustomStringConvertible {
+    case detail(String)
+    var description: String {
+        switch self {
+        case .detail(let s): return s
+        }
+    }
+}

Sources/Shotdeck/SendController.swift

@@ -16,9 +16,66 @@ extension AppModel: SendCapable {
         guard !session.isEmpty, !isSending else { return }
         setSending(true)
 
+        // Wait for any IN-FLIGHT transport/folder reconcile (chooseTransport/
+        // chooseOneDriveFolder in SettingsView.swift) to fully settle BEFORE
+        // snapshotting transport/folder below. Without this, a toggle immediately
+        // followed by Send could let send() read a state that is still mid-transition
+        // — e.g. the watcher's recordUncommented flag briefly lagging the just-chosen
+        // transport, so a freshly-sent unmarked OneDrive PDF gets misreported as an
+        // already-returned document. `Task<Void, Never>.value` never throws, and
+        // awaiting nil is an immediate no-op (AirDrop mode, or no toggle in flight).
+        await pendingReconcileTask?.value
+
+        // Snapshot BOTH the transport AND the destination folder into local `let`s
+        // ONCE, before any further `await` in this function. chooseTransport/
+        // chooseOneDriveFolder also refuse outright (status "Finish the current send
+        // first.") while isSending is true, but this snapshot is the actual fix for the
+        // send-vs-switch race: even without that guard, everything below operates on
+        // these frozen values — composePDFForSend(outbox:transport:) takes both as
+        // parameters and never re-reads `self.outboxURL`/`self.transport` after a
+        // suspension point, so a concurrent transport switch mid-send can no longer
+        // land the PDF under one transport's folder while the archive/status branch
+        // runs the other's.
+        let transport = TransportSettings.transport()
+        let destinationFolder: URL
+
+        // OneDrive mode: verify the real destination exists, is writable, AND actually
+        // accepts a real write RIGHT NOW, before composing anything. `isWritableDirectory`
+        // alone is not enough — a OneDrive Files-On-Demand directory whose provider
+        // domain is signed out can report as existing and POSIX-writable while an
+        // actual write fails, so `probeWritable` writes-fsyncs-removes a tiny real probe
+        // file to catch that. `outboxURL` is kept in sync with the resolved OneDrive
+        // folder by bootstrap/chooseTransport/chooseOneDriveFolder, but this is
+        // re-resolved fresh here (never trusted stale) so a folder that vanished or lost
+        // its permissions since then (OneDrive signed out, external volume unmounted,
+        // folder deleted, chmod'd unwritable) is caught instead of silently attempted
+        // and surfacing as a generic PDF-composition failure.
+        if transport == .oneDrive {
+            guard let folder = OneDriveLocator.resolveOneDriveFolder(),
+                  OneDriveLocator.isWritableDirectory(at: folder),
+                  OneDriveLocator.probeWritable(at: folder)
+            else {
+                let path = OneDriveLocator.resolveOneDriveFolder()?.path
+                    ?? TransportSettings.storedOneDriveFolderPath()
+                    ?? "no OneDrive folder found"
+                setResolvedOneDriveFolder(nil)
+                setStatus(ShotdeckError.oneDriveFolderUnavailable(path: path).errorDescription)
+                setSending(false)
+                return
+            }
+            destinationFolder = folder
+            setResolvedOneDriveFolder(folder)
+            if outboxURL != folder || watchFolderURL != folder {
+                setFolderURLs(outbox: folder, watch: folder)
+                try? await watcher.updateWatchFolder(folder)
+            }
+        } else {
+            destinationFolder = outboxURL
+        }
+
         let pending: ComposedSend
         do {
-            pending = try await composePDFForSend()
+            pending = try await composePDFForSend(outbox: destinationFolder, transport: transport)
         } catch {
             // Never unlink the published PDF, and never unlink the temp file either:
             // a rename failure would leave the complete document at the temp name.
@@ -27,39 +84,59 @@ extension AppModel: SendCapable {
             return
         }
 
-        guard let anchor else {
-            handleDidFailToShareItems(fileName: pending.fileName)
+        switch transport {
+        case .oneDrive:
+            // No AirDrop, no anchor needed — the PDF is already in the watched
+            // OneDrive folder. Archive immediately; the iPad marks it up in place.
+            await handleDidShareItems(fileName: pending.fileName, pageCount: pending.pageCount)
+            let pageWord = pending.pageCount == 1 ? "page" : "pages"
+            setStatus(
+                "Saved to OneDrive — \(pending.pageCount) \(pageWord). Open it in Files on your iPad."
+            )
             setSending(false)
-            return
-        }
 
-        do {
-            try Sharing.airDrop(fileURL: pending.fileURL, from: anchor) { [weak self] success in
-                guard let self else { return }
-                if success {
-                    await self.handleDidShareItems(
-                        fileName: pending.fileName,
-                        pageCount: pending.pageCount
-                    )
-                } else {
-                    self.handleDidFailToShareItems(fileName: pending.fileName)
+        case .airDrop:
+            guard let anchor else {
+                handleDidFailToShareItems(fileName: pending.fileName)
+                setSending(false)
+                return
+            }
+
+            do {
+                try Sharing.airDrop(fileURL: pending.fileURL, from: anchor) { [weak self] success in
+                    guard let self else { return }
+                    if success {
+                        await self.handleDidShareItems(
+                            fileName: pending.fileName,
+                            pageCount: pending.pageCount
+                        )
+                    } else {
+                        self.handleDidFailToShareItems(fileName: pending.fileName)
+                    }
+                    self.setSending(false)
                 }
-                self.setSending(false)
+            } catch {
+                // canPerform false, no service, or no visible window: same as cancel.
+                handleDidFailToShareItems(fileName: pending.fileName)
+                setSending(false)
             }
-        } catch {
-            // canPerform false, no service, or no visible window: same as cancel.
-            handleDidFailToShareItems(fileName: pending.fileName)
-            setSending(false)
         }
     }
 
-    /// Writes the PDF to the outbox and records its path. Does not archive the session
+    /// Writes the PDF to `outboxDir` and records its path. Does not archive the session
     /// and does not present AirDrop — that happens only after the share completes.
-    func composePDFForSend() async throws -> ComposedSend {
+    /// `outboxDir`/`transport` are passed in (values `send(anchor:)` snapshotted before
+    /// any await) rather than read from `self.outboxURL`/`self.transport` here, so a
+    /// concurrent transport switch mid-send can never redirect an in-flight compose to
+    /// a different folder. A write/rename failure specifically at the destination
+    /// folder (as opposed to composer.compose()'s own session/image-content failures)
+    /// is reported as `oneDriveFolderUnavailable` rather than the generic
+    /// `pdfCompositionFailed` when `transport == .oneDrive` — the File Provider edge
+    /// case where the folder looked writable moments ago in `send(anchor:)` but the
+    /// actual write still failed (e.g. OneDrive signed out mid-write).
+    func composePDFForSend(outbox outboxDir: URL, transport: SendTransport) async throws -> ComposedSend {
         let workingSession = session
         let composer = self.composer
-        // Live outbox (FolderSettings), not `paths.outbox` — Settings changes take effect.
-        let outboxDir = outboxURL
         let sourceDir = paths.sessionDirectory(workingSession.id)
         let fileName = PDFComposer.fileName(for: workingSession)
         let finalURL = outboxDir.appendingPathComponent(fileName)
@@ -79,14 +156,27 @@ extension AppModel: SendCapable {
             // POSIX rename onto `finalURL` replaces any same-name file in one
             // directory operation; there is never a window where the PDF is gone.
             if Darwin.rename(tempURL.path, finalURL.path) != 0 {
+                if transport == .oneDrive {
+                    throw ShotdeckError.oneDriveFolderUnavailable(path: outboxDir.path)
+                }
                 throw ShotdeckError.pdfCompositionFailed(
                     reason: "could not publish the PDF: \(String(cString: strerror(errno)))"
                 )
             }
-            try AtomicFile.fsyncDirectory(at: outboxDir)
+            do {
+                try AtomicFile.fsyncDirectory(at: outboxDir)
+            } catch {
+                if transport == .oneDrive {
+                    throw ShotdeckError.oneDriveFolderUnavailable(path: outboxDir.path)
+                }
+                throw error
+            }
         }.value
 
         guard FileManager.default.fileExists(atPath: finalURL.path) else {
+            if transport == .oneDrive {
+                throw ShotdeckError.oneDriveFolderUnavailable(path: outboxDir.path)
+            }
             throw ShotdeckError.pdfCompositionFailed(reason: "the PDF was not written to disk")
         }
         rememberLastComposedPDF(finalURL)

Sources/Shotdeck/SettingsView.swift

@@ -33,6 +33,25 @@ struct SettingsView: View {
                 .frame(minHeight: 22)
             }
 
+            GridRow {
+                Text("Send via")
+                    .font(.headline)
+                    .frame(maxWidth: .infinity, alignment: .leading)
+                    .gridCellColumns(2)
+                    .padding(.top, 6)
+            }
+
+            GridRow {
+                Picker("Send via", selection: transportBinding) {
+                    ForEach(SendTransport.allCases, id: \.self) { transport in
+                        Text(transport.displayName).tag(transport)
+                    }
+                }
+                .labelsHidden()
+                .pickerStyle(.segmented)
+                .gridCellColumns(2)
+            }
+
             GridRow {
                 Text("Folders")
                     .font(.headline)
@@ -41,17 +60,47 @@ struct SettingsView: View {
                     .padding(.top, 6)
             }
 
-            GridRow(alignment: .center) {
-                fieldLabel("Watch folder")
-                folderValue(path: model.watchFolderURL.path) {
-                    model.chooseWatchFolder()
+            if model.transport == .airDrop {
+                GridRow(alignment: .center) {
+                    fieldLabel("Watch folder")
+                    folderValue(path: model.watchFolderURL.path) {
+                        model.chooseWatchFolder()
+                    }
                 }
-            }
 
-            GridRow(alignment: .center) {
-                fieldLabel("Output folder")
-                folderValue(path: model.outboxURL.path) {
-                    model.chooseOutboxFolder()
+                GridRow(alignment: .center) {
+                    fieldLabel("Output folder")
+                    folderValue(path: model.outboxURL.path) {
+                        model.chooseOutboxFolder()
+                    }
+                }
+            } else {
+                GridRow(alignment: .center) {
+                    fieldLabel("OneDrive folder")
+                    if let folder = model.resolvedOneDriveFolder {
+                        folderValue(path: folder.path) {
+                            model.chooseOneDriveFolder()
+                        }
+                    } else {
+                        // One-line row, same shape as the normal path row: "Not found"
+                        // where the path would be, Choose… stays live. The explanation
+                        // moves to the caption below instead of wrapping this row.
+                        folderValue(path: "Not found") {
+                            model.chooseOneDriveFolder()
+                        }
+                    }
+                }
+
+                GridRow {
+                    Text(
+                        model.resolvedOneDriveFolder != nil
+                            ? "The PDF is saved here and this same folder is watched for the marked-up copy. On the iPad open it from Files > OneDrive."
+                            : "No OneDrive folder found. Sign in to OneDrive, or choose a folder."
+                    )
+                    .font(.caption)
+                    .foregroundStyle(.secondary)
+                    .fixedSize(horizontal: false, vertical: true)
+                    .gridCellColumns(2)
                 }
             }
 
@@ -68,6 +117,10 @@ struct SettingsView: View {
         .onDisappear { disarmHotkeyRecorder() }
     }
 
+    private var transportBinding: Binding<SendTransport> {
+        Binding(get: { model.transport }, set: { model.chooseTransport($0) })
+    }
+
     private func armHotkeyRecorder() {
         guard !isRecordingHotkey else { return }
         isRecordingHotkey = true
@@ -190,6 +243,87 @@ extension AppModel: SettingsWindowPresenting {
         }
     }
 
+    /// Settings "Send via" picker action. Persists the choice, recomputes the effective
+    /// outbox/watch folder for the new transport, creates the OneDrive folder if it
+    /// doesn't exist yet, and re-points the running watcher (folder + recordUncommented)
+    /// at the new state. Switching back to AirDrop restores its own stored overrides
+    /// untouched, since AirDrop and OneDrive folder settings are stored under separate keys.
+    /// Refuses while a send is in flight (send() snapshots its own folder/transport, but
+    /// switching mid-send is still confusing UX — nothing to gain by allowing it).
+    /// The async reconcile below is generation-guarded: `reconcileGeneration` is bumped
+    /// synchronously before the Task starts, and the Task checks its own snapshot against
+    /// the live value before every mutating step, so rapid toggling (this function or
+    /// chooseOneDriveFolder, in any order) always lets the LAST choice win instead of an
+    /// earlier, superseded call applying its stale folder/flag after a later one already won.
+    /// The Task's handle is stored in `pendingReconcileTask` so send() can await its
+    /// completion before snapshotting transport/folder — closing the OTHER race, where a
+    /// toggle is immediately followed by Send before this reconcile has settled.
+    func chooseTransport(_ value: SendTransport) {
+        guard !isSending else {
+            setStatus("Finish the current send first.")
+            return
+        }
+        guard value != transport else { return }
+        TransportSettings.setTransport(value)
+        setTransport(value)
+        let folders = TransportSettings.effectiveFolders()
+        if value == .oneDrive {
+            try? FileManager.default.createDirectory(
+                at: folders.outbox, withIntermediateDirectories: true
+            )
+        }
+        setFolderURLs(outbox: folders.outbox, watch: folders.watch)
+        setResolvedOneDriveFolder(OneDriveLocator.resolveOneDriveFolder())
+
+        reconcileGeneration += 1
+        let generation = reconcileGeneration
+        pendingReconcileTask = Task {
+            guard generation == self.reconcileGeneration else { return }
+            await watcher.setRecordUncommented(value == .airDrop)
+            guard generation == self.reconcileGeneration else { return }
+            do {
+                try await watcher.updateWatchFolder(folders.watch)
+            } catch {
+                guard generation == self.reconcileGeneration else { return }
+                setStatus(
+                    (error as? ShotdeckError)?.errorDescription ?? "Could not switch the watch folder."
+                )
+            }
+        }
+    }
+
+    /// Refuses while a send is in flight, same reasoning as chooseTransport. See
+    /// chooseTransport's doc comment for the generation-guard mechanism shared here.
+    func chooseOneDriveFolder() {
+        guard !isSending else {
+            setStatus("Finish the current send first.")
+            return
+        }
+        let start = resolvedOneDriveFolder ?? FileManager.default.homeDirectoryForCurrentUser
+        guard let url = chooseDirectory(startingAt: start) else { return }
+        TransportSettings.setOneDriveFolder(url)
+        try? FileManager.default.createDirectory(at: url, withIntermediateDirectories: true)
+        setResolvedOneDriveFolder(OneDriveLocator.resolveOneDriveFolder())
+        guard transport == .oneDrive else { return }
+        setFolderURLs(outbox: url, watch: url)
+
+        reconcileGeneration += 1
+        let generation = reconcileGeneration
+        pendingReconcileTask = Task {
+            guard generation == self.reconcileGeneration else { return }
+            do {
+                try await watcher.updateWatchFolder(url)
+                guard generation == self.reconcileGeneration else { return }
+                setStatus("OneDrive folder set to \(url.lastPathComponent).")
+            } catch {
+                guard generation == self.reconcileGeneration else { return }
+                setStatus(
+                    (error as? ShotdeckError)?.errorDescription ?? "Could not switch the watch folder."
+                )
+            }
+        }
+    }
+
     private func chooseDirectory(startingAt directory: URL) -> URL? {
         let panel = NSOpenPanel()
         panel.canChooseDirectories = true

Sources/Shotdeck/UpdateChecker.swift

@@ -2,6 +2,7 @@ import AppKit
 import CryptoKit
 import Foundation
 import Security
+import ShotdeckCore
 
 /// Built-in updater. Checks an appcast, stages a verified payload, and installs
 /// only when the user clicks the menu row — never automatically.
@@ -31,6 +32,12 @@ final class UpdateChecker {
     private var repeatingTimer: Timer?
     private var firstCheckTask: Task<Void, Never>?
     private var stagingDirectory: URL?
+    /// Snapshot-only override for previousVersion; when snapshotUsesPreviousVersionOverride is true,
+    /// this value (including nil) is returned instead of checking the file system.
+    var snapshotPreviousVersionOverride: String?
+    var snapshotUsesPreviousVersionOverride: Bool = false
+    /// Test seam: override appcast JSON. When set, returns this instead of fetching from URL.
+    var testAppcastJSON: String?
 
     init() {
         let config = URLSessionConfiguration.ephemeral
@@ -85,7 +92,12 @@ final class UpdateChecker {
 
         guard Self.isNewer(appcast.version, than: Self.currentVersion()) else {
             clearOffer()
-            statusMessage = manual ? "Redline \(Self.currentVersion()) is up to date." : nil
+            if manual {
+                let timestamp = DubaiTime.checkTime(lastCheckedAt ?? Date())
+                statusMessage = "Redline \(Self.currentVersion()) is up to date, checked \(timestamp)"
+            } else {
+                statusMessage = nil
+            }
             onChecked?()
             return
         }
@@ -93,7 +105,7 @@ final class UpdateChecker {
         do {
             try await downloadAndStage(appcast)
             availableUpdate = (version: appcast.version, notes: appcast.notes ?? "")
-            statusMessage = nil
+            statusMessage = manual ? "Update to \(appcast.version) is ready" : nil
         } catch UpdateCheckError.checksumMismatch {
             discardStaging()
             availableUpdate = nil
@@ -226,8 +238,11 @@ final class UpdateChecker {
     }
 
     /// The version recorded in `Redline.app.previous`'s Info.plist, or nil when no
-    /// rollback copy exists.
+    /// rollback copy exists. Respects the snapshot-only override for panel rendering.
     func previousVersion(target: URL = UpdateChecker.defaultInstallTarget) -> String? {
+        if snapshotUsesPreviousVersionOverride {
+            return snapshotPreviousVersionOverride
+        }
         let previousURL = target.deletingLastPathComponent().appendingPathComponent("Redline.app.previous")
         let plistURL = previousURL.appendingPathComponent("Contents/Info.plist")
         guard let plist = NSDictionary(contentsOf: plistURL) as? [String: Any] else { return nil }
@@ -346,7 +361,12 @@ final class UpdateChecker {
     }
 
     private func fetchAppcast() async throws -> Appcast {
-        let data = try await fetchData(from: Self.resolvedAppcastURL())
+        let data: Data
+        if let testJSON = testAppcastJSON {
+            data = testJSON.data(using: .utf8) ?? Data()
+        } else {
+            data = try await fetchData(from: Self.resolvedAppcastURL())
+        }
         return try JSONDecoder().decode(Appcast.self, from: data)
     }
 

Sources/Shotdeck/main.swift

@@ -7,6 +7,9 @@ import ShotdeckCore
 if ProcessInfo.processInfo.environment["SHOTDECK_SNAPSHOT_DIR"] != nil {
     MainActor.assumeIsolated { PanelSnapshot.runIfRequested() }
 }
+if ProcessInfo.processInfo.environment["REDLINE_SELFTEST_PHASE"] == "onedrive" {
+    MainActor.assumeIsolated { PickerSelfTest.runOneDriveOnlyIfRequested() }
+}
 if ProcessInfo.processInfo.environment["SHOTDECK_PICKER_SELFTEST"] != nil {
     MainActor.assumeIsolated { PickerSelfTest.runIfRequested() }
 }
@@ -71,9 +74,18 @@ final class AppDelegate: NSObject, NSApplicationDelegate {
         Task { await model.bootstrap() }
     }
 
-    private static func makeLaunchModel() -> AppModel {
+    /// Builds the model exactly the way the real app launches: paths come from
+    /// `TransportSettings.resolvedAppSupportPaths()` — transport-aware, so the watcher
+    /// this feeds is never seeded with a stale AirDrop folder while OneDrive is the
+    /// persisted transport (that was the BLOCKER this function used to have, when it
+    /// called the AirDrop-only `FolderSettings.resolvedAppSupportPaths()` instead).
+    /// `appSupportRoot` exists only so PickerSelfTest's relaunch-simulation sub-step can
+    /// point this at a temp directory instead of the real
+    /// ~/Library/Application Support/Shotdeck — production always calls this with no
+    /// argument (the real root). Internal, not private, for that same reason.
+    static func makeLaunchModel(appSupportRoot: URL? = nil) -> AppModel {
         do {
-            let paths = try FolderSettings.resolvedAppSupportPaths()
+            let paths = try TransportSettings.resolvedAppSupportPaths(root: appSupportRoot)
             return try makeModel(paths: paths)
         } catch {
             Log.ui.critical(

Sources/ShotdeckCore/Model/ShotdeckError.swift

@@ -10,6 +10,7 @@ public enum ShotdeckError: Error, LocalizedError, Sendable {
     case pdfCompositionFailed(reason: String)
     case airDropUnavailable
     case noCommentedReturns
+    case oneDriveFolderUnavailable(path: String)
 
     public var errorDescription: String? {
         switch self {
@@ -31,6 +32,8 @@ public enum ShotdeckError: Error, LocalizedError, Sendable {
             return "AirDrop is not available right now."
         case .noCommentedReturns:
             return "None of the returned PDFs have comments on them."
+        case .oneDriveFolderUnavailable(let path):
+            return "Your OneDrive folder is not available: \(path). Check that OneDrive is signed in, or choose another folder in Settings."
         }
     }
 }

Sources/ShotdeckCore/Returns/ReturnWatcher.swift

@@ -10,6 +10,21 @@ public actor ReturnWatcher {
     private var bridge: FSEventBridge?
     private var pendingScanTask: Task<Void, Never>?
     private let eventQueue = DispatchQueue(label: "ai.flowmaster.shotdeck.returns.fsevents")
+    /// When false, a document with zero human marks is neither recorded into the ledger
+    /// nor included in scanNow's/onChange's results — needed for OneDrive mode, where the
+    /// outbox and watch folder are the same folder and a freshly written, unmarked PDF
+    /// must not be treated as a return. Defaults to true (today's AirDrop behaviour).
+    /// A document that IS commented is always recorded, regardless of this flag.
+    public var recordUncommented: Bool = true
+
+    /// The folder this watcher is CURRENTLY seeded to scan/watch — whatever `init`
+    /// last set it to, or `updateWatchFolder` since. Exposed so tests can observe the
+    /// watcher's seeded folder directly (e.g. right after construction, before
+    /// `start()`/`updateWatchFolder()` ever run) rather than only inferring it
+    /// indirectly through `scanNow()`'s behavior.
+    public var currentWatchFolder: URL {
+        watchFolder
+    }
 
     /// Watch folder is `paths.watchFolder`, which production constructs from
     /// `FolderSettings.resolve().watch`. This type never calls FolderSettings;
@@ -29,6 +44,12 @@ public actor ReturnWatcher {
         onChange(found)
     }
 
+    /// Sets `recordUncommented`. A `func` (not a plain property set) only because
+    /// callers outside this actor must `await` it like any other actor mutation.
+    public func setRecordUncommented(_ value: Bool) {
+        recordUncommented = value
+    }
+
     /// 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() {
@@ -77,6 +98,7 @@ public actor ReturnWatcher {
             guard let document = PDFDocument(url: url),
                   AnnotationInspector.isShotdeckDocument(document) else { continue }
             guard let inspected = try? AnnotationInspector.inspect(fileURL: url) else { continue }
+            if !recordUncommented, !inspected.isCommented { continue }
             try await ledger.record(inspected)
             results.append(inspected)
         }

Sources/ShotdeckCore/Support/AppSupportPaths.swift

@@ -11,12 +11,6 @@ public struct AppSupportPaths: Sendable {
     /// 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,
@@ -29,10 +23,25 @@ public struct AppSupportPaths: Sendable {
             appropriateFor: nil,
             create: true
         )
-        let root = appSupportParent.appendingPathComponent("Shotdeck", isDirectory: true)
+        let root = try standardRoot(fileManager: fileManager)
         return try AppSupportPaths(root: root, outbox: desktop, watchFolder: downloads)
     }
 
+    /// The standard `~/Library/Application Support/Shotdeck` root. Shared by
+    /// `standard()`, `FolderSettings.resolvedAppSupportPaths()`, and
+    /// `TransportSettings.resolvedAppSupportPaths()` so all three agree on where the
+    /// root lives — the folder-resolution logic (AirDrop-only vs transport-aware)
+    /// differs between those, the root computation never should.
+    public static func standardRoot(fileManager: FileManager = .default) throws -> URL {
+        let appSupportParent = try fileManager.url(
+            for: .applicationSupportDirectory,
+            in: .userDomainMask,
+            appropriateFor: nil,
+            create: true
+        )
+        return appSupportParent.appendingPathComponent("Shotdeck", isDirectory: true)
+    }
+
     /// Test paths rooted anywhere. Every directory is created if missing.
     public init(root: URL, outbox: URL, watchFolder: URL) throws {
         self.root = root

Sources/ShotdeckCore/Support/DubaiTime.swift

@@ -3,6 +3,7 @@ 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")
+    private static let checkTimeFormatter = LockedDateFormatter(dateFormat: "HH:mm 'Dubai'")
 
     public static func stamp(_ date: Date) -> String {
         stampFormatter.string(from: date)
@@ -11,6 +12,10 @@ public enum DubaiTime {
     public static func fileStamp(_ date: Date) -> String {
         fileStampFormatter.string(from: date)
     }
+
+    public static func checkTime(_ date: Date) -> String {
+        checkTimeFormatter.string(from: date)
+    }
 }
 
 /// DateFormatter is not Sendable. This holder is the only shared mutable state

Sources/ShotdeckCore/Support/FolderSettings.swift

@@ -70,15 +70,7 @@ public enum FolderSettings {
         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 resolvedRoot = try root ?? AppSupportPaths.standardRoot(fileManager: fileManager)
         let folders = resolve(defaults: defaults, fileManager: fileManager)
         return try AppSupportPaths(root: resolvedRoot, outbox: folders.outbox, watchFolder: folders.watch)
     }

Sources/ShotdeckCore/Support/TransportSettings.swift

@@ -0,0 +1,221 @@
+import Foundation
+
+/// The two ways a composed PDF can reach the iPad and come back marked up.
+public enum SendTransport: String, Codable, Sendable, CaseIterable {
+    case airDrop
+    case oneDrive
+
+    public var displayName: String {
+        switch self {
+        case .airDrop: return "AirDrop"
+        case .oneDrive: return "OneDrive folder"
+        }
+    }
+}
+
+/// User-configurable transport choice plus the OneDrive folder override, backed by
+/// UserDefaults the same way `FolderSettings` is. See `FolderSettings` for why a plain
+/// path (not a security-scoped bookmark) is correct for this unsandboxed app.
+public enum TransportSettings {
+    public static let transportDefaultsKey = "ai.flowmaster.shotdeck.transport"
+    public static let oneDriveFolderDefaultsKey = "ai.flowmaster.shotdeck.oneDriveFolder"
+
+    /// Defaults to `.airDrop` when unset or when the stored value cannot be parsed.
+    public static func transport(defaults: UserDefaults = .standard) -> SendTransport {
+        guard let raw = defaults.string(forKey: transportDefaultsKey),
+              let value = SendTransport(rawValue: raw)
+        else { return .airDrop }
+        return value
+    }
+
+    public static func setTransport(_ value: SendTransport, defaults: UserDefaults = .standard) {
+        defaults.set(value.rawValue, forKey: transportDefaultsKey)
+    }
+
+    /// Raw stored path (or nil if never set / cleared). Does NOT validate that the
+    /// directory still exists.
+    public static func storedOneDriveFolderPath(defaults: UserDefaults = .standard) -> String? {
+        defaults.string(forKey: oneDriveFolderDefaultsKey)
+    }
+
+    public static func setOneDriveFolder(_ url: URL, defaults: UserDefaults = .standard) {
+        defaults.set(url.path, forKey: oneDriveFolderDefaultsKey)
+    }
+
+    public static func resetOneDriveFolder(defaults: UserDefaults = .standard) {
+        defaults.removeObject(forKey: oneDriveFolderDefaultsKey)
+    }
+
+    /// The outbox/watch folders Redline should actually use right now, for the current
+    /// transport. AirDrop mode delegates to `FolderSettings.resolve()` unchanged.
+    /// OneDrive mode uses the SAME folder for both outbox and watch — see
+    /// `OneDriveLocator.resolveOneDriveFolder`. When no OneDrive folder can be resolved
+    /// at all (no sync root, no override), this falls back to the AirDrop folders so the
+    /// app always has somewhere to write; `send(anchor:)` performs its own live
+    /// existence check before ever composing into a OneDrive send, so that fallback is
+    /// never mistaken for a valid OneDrive destination.
+    public static func effectiveFolders(
+        defaults: UserDefaults = .standard,
+        fileManager: FileManager = .default
+    ) -> (outbox: URL, watch: URL, transport: SendTransport) {
+        let transport = transport(defaults: defaults)
+        switch transport {
+        case .airDrop:
+            let folders = FolderSettings.resolve(defaults: defaults, fileManager: fileManager)
+            return (folders.outbox, folders.watch, transport)
+        case .oneDrive:
+            if let folder = OneDriveLocator.resolveOneDriveFolder(
+                defaults: defaults,
+                home: fileManager.homeDirectoryForCurrentUser,
+                fileManager: fileManager
+            ) {
+                return (folder, folder, transport)
+            }
+            let folders = FolderSettings.resolve(defaults: defaults, fileManager: fileManager)
+            return (folders.outbox, folders.watch, transport)
+        }
+    }
+
+    /// Builds an `AppSupportPaths` using `root` (defaults to the standard
+    /// `~/Library/Application Support/Shotdeck` when nil) plus whatever
+    /// `effectiveFolders()` returns for outbox/watch. Unlike
+    /// `FolderSettings.resolvedAppSupportPaths()` (AirDrop-only), this is
+    /// transport-aware — it is the ONLY function launch code should use to build its
+    /// paths, so the watcher it feeds is never seeded with a stale AirDrop folder while
+    /// OneDrive is the persisted transport. `root` is exposed purely so tests (and the
+    /// ONEDRIVE-SELFTEST relaunch simulation) 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 = try root ?? AppSupportPaths.standardRoot(fileManager: fileManager)
+        let folders = effectiveFolders(defaults: defaults, fileManager: fileManager)
+        return try AppSupportPaths(root: resolvedRoot, outbox: folders.outbox, watchFolder: folders.watch)
+    }
+}
+
+/// Pure path logic for locating a OneDrive sync root under
+/// `~/Library/CloudStorage` and the Redline folder inside it. No side effects — never
+/// creates a directory. Fully unit-testable with a fake home tree.
+public enum OneDriveLocator {
+    /// Every directory directly under `<home>/Library/CloudStorage` whose name starts
+    /// with "OneDrive-", sorted so a name containing "MMD" (case-insensitive) sorts
+    /// first, then alphabetically. Empty when CloudStorage does not exist.
+    public static func syncRoots(
+        home: URL = FileManager.default.homeDirectoryForCurrentUser,
+        fileManager: FileManager = .default
+    ) -> [URL] {
+        let cloudStorage = home.appendingPathComponent("Library/CloudStorage", isDirectory: true)
+        var isDirectory: ObjCBool = false
+        guard fileManager.fileExists(atPath: cloudStorage.path, isDirectory: &isDirectory),
+              isDirectory.boolValue
+        else { return [] }
+
+        let items = (try? fileManager.contentsOfDirectory(
+            at: cloudStorage,
+            includingPropertiesForKeys: [.isDirectoryKey],
+            options: [.skipsHiddenFiles]
+        )) ?? []
+
+        let roots = items.filter { url in
+            guard url.lastPathComponent.hasPrefix("OneDrive-") else { return false }
+            var itemIsDirectory: ObjCBool = false
+            let exists = fileManager.fileExists(atPath: url.path, isDirectory: &itemIsDirectory)
+            return exists && itemIsDirectory.boolValue
+        }
+
+        return roots.sorted { a, b in
+            let aName = a.lastPathComponent
+            let bName = b.lastPathComponent
+            let aIsMMD = aName.localizedCaseInsensitiveContains("MMD")
+            let bIsMMD = bName.localizedCaseInsensitiveContains("MMD")
+            if aIsMMD != bIsMMD { return aIsMMD }
+            return aName.localizedStandardCompare(bName) == .orderedAscending
+        }
+    }
+
+    /// First sync root's "Redline" subfolder, or nil when there is no sync root at all.
+    public static func defaultRedlineFolder(
+        home: URL = FileManager.default.homeDirectoryForCurrentUser,
+        fileManager: FileManager = .default
+    ) -> URL? {
+        guard let first = syncRoots(home: home, fileManager: fileManager).first else { return nil }
+        return first.appendingPathComponent("Redline", isDirectory: true)
+    }
+
+    /// The stored override when it is set AND still exists as a directory; otherwise
+    /// `defaultRedlineFolder`. Never creates anything.
+    public static func resolveOneDriveFolder(
+        defaults: UserDefaults = .standard,
+        home: URL = FileManager.default.homeDirectoryForCurrentUser,
+        fileManager: FileManager = .default
+    ) -> URL? {
+        if let storedPath = TransportSettings.storedOneDriveFolderPath(defaults: defaults) {
+            var isDirectory: ObjCBool = false
+            let exists = fileManager.fileExists(atPath: storedPath, isDirectory: &isDirectory)
+            if exists, isDirectory.boolValue {
+                return URL(fileURLWithPath: storedPath, isDirectory: true)
+            }
+        }
+        return defaultRedlineFolder(home: home, fileManager: fileManager)
+    }
+
+    /// True when `url` exists as a directory AND is writable by the current process.
+    /// The live check `send(anchor:)` performs before ever composing into a OneDrive
+    /// destination — a directory that exists but has had its permissions revoked (e.g.
+    /// `chmod 500`) must be treated as unavailable, not silently attempted and
+    /// surfaced as a generic PDF-composition failure.
+    public static func isWritableDirectory(
+        at url: URL,
+        fileManager: FileManager = .default
+    ) -> Bool {
+        var isDirectory: ObjCBool = false
+        let exists = fileManager.fileExists(atPath: url.path, isDirectory: &isDirectory)
+        guard exists, isDirectory.boolValue else { return false }
+        return fileManager.isWritableFile(atPath: url.path)
+    }
+
+    /// Writes a tiny probe file into `folder`, fsyncs it, then removes it — the only
+    /// reliable way to catch a OneDrive Files-On-Demand directory whose provider domain
+    /// is signed out: such a directory can report as existing and POSIX-writable
+    /// (`isWritableDirectory` returns true) while an actual write fails. True only when
+    /// the write, fsync, AND removal of the probe file all succeed; any failure at any
+    /// of those steps means false, so the caller treats the folder as unavailable
+    /// rather than proceeding to compose a real PDF into it.
+    public static func probeWritable(
+        at folder: URL,
+        fileManager: FileManager = .default
+    ) -> Bool {
+        let probeURL = folder.appendingPathComponent(".redline-probe-\(UUID().uuidString)")
+        // Belt-and-suspenders cleanup, unconditional: AtomicFile.write renames the temp
+        // file onto probeURL and THEN fsyncs the containing directory — if that last
+        // fsync throws, the probe file already exists on disk but the catch below
+        // returns false before ever reaching the explicit removeItem call. And if the
+        // explicit removeItem itself throws, this is the only retry it gets. Either
+        // way, never leave the probe file behind just because we're about to return.
+        defer {
+            if fileManager.fileExists(atPath: probeURL.path) {
+                try? fileManager.removeItem(at: probeURL)
+            }
+        }
+
+        do {
+            try AtomicFile.write(Data(), to: probeURL)
+        } catch {
+            return false
+        }
+
+        do {
+            try fileManager.removeItem(at: probeURL)
+        } catch {
+            return false
+        }
+
+        // Only true when the explicit removal above actually succeeded AND the file is
+        // confirmed gone — never trust a removeItem call that returned without throwing
+        // as proof of anything on a File Provider domain.
+        return !fileManager.fileExists(atPath: probeURL.path)
+    }
+}

Tests/ShotdeckCoreTests/OneDriveLocatorTests.swift

@@ -0,0 +1,125 @@
+import Foundation
+import Testing
+import ShotdeckCore
+
+@Test
+func syncRootsFindsOneDriveDirsMMDFirstIgnoresNonDirsAndOtherProviders() throws {
+    let home = try makeFakeHome()
+    defer { try? FileManager.default.removeItem(at: home) }
+    let cloudStorage = home.appendingPathComponent("Library/CloudStorage", isDirectory: true)
+    try FileManager.default.createDirectory(at: cloudStorage, withIntermediateDirectories: true)
+
+    try FileManager.default.createDirectory(
+        at: cloudStorage.appendingPathComponent("OneDrive-Flowmaster", isDirectory: true),
+        withIntermediateDirectories: true
+    )
+    try FileManager.default.createDirectory(
+        at: cloudStorage.appendingPathComponent("OneDrive-MMDGROUP", isDirectory: true),
+        withIntermediateDirectories: true
+    )
+    try FileManager.default.createDirectory(
+        at: cloudStorage.appendingPathComponent("GoogleDrive-x", isDirectory: true),
+        withIntermediateDirectories: true
+    )
+    // A plain FILE (not a directory) named like a OneDrive root must be ignored.
+    FileManager.default.createFile(
+        atPath: cloudStorage.appendingPathComponent("OneDrive-notadir").path,
+        contents: Data("not a directory".utf8)
+    )
+
+    let roots = OneDriveLocator.syncRoots(home: home, fileManager: .default)
+
+    #expect(roots.map(\.lastPathComponent) == ["OneDrive-MMDGROUP", "OneDrive-Flowmaster"])
+}
+
+@Test
+func syncRootsEmptyAndDefaultFolderNilWithNoCloudStorageDirectory() throws {
+    let home = try makeFakeHome()
+    defer { try? FileManager.default.removeItem(at: home) }
+    // No Library/CloudStorage created at all.
+
+    let roots = OneDriveLocator.syncRoots(home: home, fileManager: .default)
+    #expect(roots.isEmpty)
+
+    let defaultFolder = OneDriveLocator.defaultRedlineFolder(home: home, fileManager: .default)
+    #expect(defaultFolder == nil)
+}
+
+@Test
+func defaultRedlineFolderIsFirstSyncRootPlusRedline() throws {
+    let home = try makeFakeHome()
+    defer { try? FileManager.default.removeItem(at: home) }
+    let cloudStorage = home.appendingPathComponent("Library/CloudStorage", isDirectory: true)
+    try FileManager.default.createDirectory(
+        at: cloudStorage.appendingPathComponent("OneDrive-MMDGROUP", isDirectory: true),
+        withIntermediateDirectories: true
+    )
+    try FileManager.default.createDirectory(
+        at: cloudStorage.appendingPathComponent("OneDrive-Flowmaster", isDirectory: true),
+        withIntermediateDirectories: true
+    )
+
+    let defaultFolder = try #require(
+        OneDriveLocator.defaultRedlineFolder(home: home, fileManager: .default)
+    )
+    // Derive "expected" from syncRoots() itself (already covered by its own dedicated
+    // test) rather than hand-building the path string — FileManager's directory
+    // enumeration can canonicalize /var -> /private/var and the two constructions
+    // otherwise disagree on that even for a URL that already exists.
+    let expectedRoot = try #require(OneDriveLocator.syncRoots(home: home, fileManager: .default).first)
+    let expected = expectedRoot.appendingPathComponent("Redline", isDirectory: true)
+    #expect(defaultFolder.path == expected.path)
+}
+
+@Test
+func resolveOneDriveFolderPrefersAnExistingStoredOverride() throws {
+    let home = try makeFakeHome()
+    defer { try? FileManager.default.removeItem(at: home) }
+    let cloudStorage = home.appendingPathComponent("Library/CloudStorage", isDirectory: true)
+    try FileManager.default.createDirectory(
+        at: cloudStorage.appendingPathComponent("OneDrive-MMDGROUP", isDirectory: true),
+        withIntermediateDirectories: true
+    )
+
+    let suite = try makeTransportDefaultsSuite()
+    defer { tearDownTransportSuite(suite) }
+    let override = try makeTransportTemporaryDirectory(prefix: "shotdeck-onedrive-override")
+    defer { try? FileManager.default.removeItem(at: override) }
+    TransportSettings.setOneDriveFolder(override, defaults: suite.defaults)
+
+    let resolved = OneDriveLocator.resolveOneDriveFolder(
+        defaults: suite.defaults, home: home, fileManager: .default
+    )
+    #expect(resolved?.path == override.path)
+}
+
+@Test
+func resolveOneDriveFolderIgnoresAStoredPathThatNoLongerExists() throws {
+    let home = try makeFakeHome()
+    defer { try? FileManager.default.removeItem(at: home) }
+    let cloudStorage = home.appendingPathComponent("Library/CloudStorage", isDirectory: true)
+    try FileManager.default.createDirectory(
+        at: cloudStorage.appendingPathComponent("OneDrive-MMDGROUP", isDirectory: true),
+        withIntermediateDirectories: true
+    )
+
+    let suite = try makeTransportDefaultsSuite()
+    defer { tearDownTransportSuite(suite) }
+    let goneOverride = try makeTransportTemporaryDirectory(prefix: "shotdeck-onedrive-gone")
+    TransportSettings.setOneDriveFolder(goneOverride, defaults: suite.defaults)
+    try FileManager.default.removeItem(at: goneOverride)
+
+    let resolved = OneDriveLocator.resolveOneDriveFolder(
+        defaults: suite.defaults, home: home, fileManager: .default
+    )
+    let expectedRoot = try #require(OneDriveLocator.syncRoots(home: home, fileManager: .default).first)
+    let expected = expectedRoot.appendingPathComponent("Redline", isDirectory: true)
+    #expect(resolved?.path == expected.path)
+}
+
+private func makeFakeHome() throws -> URL {
+    let home = FileManager.default.temporaryDirectory
+        .appendingPathComponent("shotdeck-fake-home-\(UUID().uuidString)", isDirectory: true)
+    try FileManager.default.createDirectory(at: home, withIntermediateDirectories: true)
+    return home
+}

Tests/ShotdeckCoreTests/ReturnWatcherTests.swift

@@ -230,3 +230,162 @@ func w27_fsEventsCallbackFiresOnRealArrival() async throws {
         await watcher.stop()
     }
 }
+
+@Test("recordUncommented defaults to true: an unmarked PDF is still recorded (AirDrop behaviour unchanged)")
+func recordUncommentedDefaultTrueRecordsAnUnmarkedPDF() 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("Redline-20260905-090000.pdf")
+
+    try makePDF(at: pdfURL, pageCount: 1, creator: "Redline", annotations: [])
+
+    let found = try await watcher.scanNow()
+    #expect(found.count == 1)
+    #expect(found.first?.isCommented == false)
+
+    let all = try await ledger.all()
+    #expect(all.count == 1)
+}
+
+@Test("recordUncommented=false: an unmarked PDF is not recorded or returned; marking it up in place gets it recorded")
+func recordUncommentedFalseSkipsUnmarkedThenRecordsAfterInPlaceMarkup() 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)
+    await watcher.setRecordUncommented(false)
+    let pdfURL = paths.watchFolder.appendingPathComponent("Redline-20260905-091500.pdf")
+
+    // OneDrive mode: the PDF is freshly written here (by "send"), unmarked so far.
+    try makePDF(at: pdfURL, pageCount: 1, creator: "Redline", annotations: [])
+
+    let beforeMarkup = try await watcher.scanNow()
+    #expect(beforeMarkup.isEmpty)
+    let allBefore = try await ledger.all()
+    #expect(allBefore.isEmpty)
+
+    // What the iPad does: mark it up in place, in the SAME folder, then save.
+    let document = try #require(PDFDocument(url: pdfURL))
+    let page = try #require(document.page(at: 0))
+    page.addAnnotation(makeAnnotation(.ink, bounds: CGRect(x: 100, y: 100, width: 120, height: 50)))
+    #expect(document.write(to: pdfURL))
+
+    let afterMarkup = try await watcher.scanNow()
+    #expect(afterMarkup.count == 1)
+    #expect(afterMarkup.first?.isCommented == true)
+
+    let commented = try await ledger.commented()
+    #expect(commented.count == 1)
+    #expect(commented.first?.fileURL.resolvingSymlinksInPath().path == pdfURL.resolvingSymlinksInPath().path)
+}
+
+// MARK: - Launch-paths BLOCKER regression (adversarial review, 20260905)
+//
+// The bug: AppDelegate.makeLaunchModel() built `paths` via the AirDrop-only
+// FolderSettings.resolvedAppSupportPaths(), so ReturnWatcher's internal watchFolder
+// (seeded from paths.watchFolder in its own init) was the AirDrop folder even when
+// OneDrive was the persisted transport, and bootstrap() never reconciled it before
+// starting. Net effect: PDFs went to OneDrive but FSEvents kept watching the stale
+// AirDrop folder for the whole session — marked-up returns were never detected.
+// The fix: launch paths now come from TransportSettings.resolvedAppSupportPaths()
+// (transport-aware), and AppModel.bootstrap() unconditionally reconciles the watcher's
+// folder via updateWatchFolder() before it starts. These two tests characterize the
+// bug (still reproducible via the old AirDrop-only construction) and prove the fix
+// (the real launch-construction path, end to end).
+
+@Test("Launch regression (fix): OneDrive persisted -> transport-aware launch paths -> bootstrap-style reconcile -> a marked PDF is detected")
+func launchStyleConstructionWithOneDriveTransportDetectsAMarkedReturn() async throws {
+    let suite = try makeTransportDefaultsSuite()
+    defer { tearDownTransportSuite(suite) }
+    let oneDriveFolder = try makeTransportTemporaryDirectory(prefix: "shotdeck-launch-onedrive")
+    defer { try? FileManager.default.removeItem(at: oneDriveFolder) }
+    let appSupportRoot = try makeTransportTemporaryDirectory(prefix: "shotdeck-launch-approot")
+    defer { try? FileManager.default.removeItem(at: appSupportRoot) }
+
+    TransportSettings.setTransport(.oneDrive, defaults: suite.defaults)
+    TransportSettings.setOneDriveFolder(oneDriveFolder, defaults: suite.defaults)
+
+    // Exactly what AppDelegate.makeLaunchModel() now does: build launch paths from the
+    // transport-aware resolver — the fix, NOT FolderSettings.resolvedAppSupportPaths(),
+    // which is AirDrop-only and is the root cause the next test characterizes.
+    let paths = try TransportSettings.resolvedAppSupportPaths(
+        root: appSupportRoot, defaults: suite.defaults, fileManager: .default
+    )
+    #expect(paths.outbox.path == oneDriveFolder.path)
+    #expect(paths.watchFolder.path == oneDriveFolder.path)
+
+    let ledger = try ReturnLedger(paths: paths)
+    let watcher = ReturnWatcher(paths: paths, ledger: ledger)
+
+    // What AppModel.bootstrap() now does, unconditionally, before watcher.start():
+    await watcher.setRecordUncommented(false)   // transport == .oneDrive
+    try await watcher.updateWatchFolder(paths.watchFolder)
+
+    let pdfURL = oneDriveFolder.appendingPathComponent("Redline-20260905-100000.pdf")
+    try makePDF(
+        at: pdfURL, pageCount: 1, creator: "Redline",
+        annotations: [(page: 0, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 100, y: 100, width: 120, height: 50)
+        ))]
+    )
+
+    let found = try await watcher.scanNow()
+    #expect(found.contains(where: {
+        $0.fileURL.resolvingSymlinksInPath().path == pdfURL.resolvingSymlinksInPath().path && $0.isCommented
+    }))
+
+    let commented = try await ledger.commented()
+    #expect(commented.contains(where: {
+        $0.fileURL.resolvingSymlinksInPath().path == pdfURL.resolvingSymlinksInPath().path
+    }))
+}
+
+@Test("Launch regression (characterizes the bug): AirDrop-only launch paths with no reconcile miss an OneDrive-mode return")
+func airDropOnlyLaunchPathsWithoutReconcileMissesAMarkedOneDriveReturn() async throws {
+    let suite = try makeTransportDefaultsSuite()
+    defer { tearDownTransportSuite(suite) }
+    let oneDriveFolder = try makeTransportTemporaryDirectory(prefix: "shotdeck-buggy-onedrive")
+    defer { try? FileManager.default.removeItem(at: oneDriveFolder) }
+    // A configured AirDrop watch-folder override, isolated to a temp dir — NOT the real
+    // ~/Downloads, which may already hold real marked-up Redline PDFs from actual use
+    // and would make this test's "found.isEmpty" assertion depend on the state of
+    // Ben's real Downloads folder instead of the isolated fixture under test.
+    let staleAirDropFolder = try makeTransportTemporaryDirectory(prefix: "shotdeck-buggy-airdrop-stale")
+    defer { try? FileManager.default.removeItem(at: staleAirDropFolder) }
+    let appSupportRoot = try makeTransportTemporaryDirectory(prefix: "shotdeck-buggy-approot")
+    defer { try? FileManager.default.removeItem(at: appSupportRoot) }
+
+    TransportSettings.setTransport(.oneDrive, defaults: suite.defaults)
+    TransportSettings.setOneDriveFolder(oneDriveFolder, defaults: suite.defaults)
+    FolderSettings.setWatchFolder(staleAirDropFolder, defaults: suite.defaults)
+
+    // The BUG's exact construction: FolderSettings.resolvedAppSupportPaths() ignores
+    // the persisted transport entirely and always resolves the AirDrop folders.
+    let buggyPaths = try FolderSettings.resolvedAppSupportPaths(root: appSupportRoot, defaults: suite.defaults)
+    #expect(buggyPaths.watchFolder.path == staleAirDropFolder.path)
+    #expect(buggyPaths.watchFolder.path != oneDriveFolder.path)
+
+    let ledger = try ReturnLedger(paths: buggyPaths)
+    let watcher = ReturnWatcher(paths: buggyPaths, ledger: ledger)
+    // The old bootstrap(): recordUncommented was set, but there was NO
+    // updateWatchFolder() call before start() to reconcile the folder.
+    await watcher.setRecordUncommented(false)
+
+    let pdfURL = oneDriveFolder.appendingPathComponent("Redline-20260905-100100.pdf")
+    try makePDF(
+        at: pdfURL, pageCount: 1, creator: "Redline",
+        annotations: [(page: 0, annotation: makeAnnotation(
+            .ink, bounds: CGRect(x: 100, y: 100, width: 120, height: 50)
+        ))]
+    )
+
+    // The watcher is still pointed at the stale (configured-AirDrop) watch folder, so
+    // scanning it — NOT the OneDrive folder the PDF actually landed in — finds nothing.
+    // This is the exact BLOCKER the fix above closes.
+    let found = try await watcher.scanNow()
+    #expect(found.isEmpty)
+}

Tests/ShotdeckCoreTests/TransportSettingsTests.swift

@@ -0,0 +1,227 @@
+import Foundation
+import Testing
+import ShotdeckCore
+
+@Test
+func transportDefaultsToAirDropWhenUnset() throws {
+    let suite = try makeTransportDefaultsSuite()
+    defer { tearDownTransportSuite(suite) }
+
+    #expect(TransportSettings.transport(defaults: suite.defaults) == .airDrop)
+}
+
+@Test
+func setTransportRoundTrips() throws {
+    let suite = try makeTransportDefaultsSuite()
+    defer { tearDownTransportSuite(suite) }
+
+    TransportSettings.setTransport(.oneDrive, defaults: suite.defaults)
+    #expect(TransportSettings.transport(defaults: suite.defaults) == .oneDrive)
+
+    TransportSettings.setTransport(.airDrop, defaults: suite.defaults)
+    #expect(TransportSettings.transport(defaults: suite.defaults) == .airDrop)
+}
+
+@Test
+func garbageStoredTransportFallsBackToAirDrop() throws {
+    let suite = try makeTransportDefaultsSuite()
+    defer { tearDownTransportSuite(suite) }
+
+    suite.defaults.set("not-a-real-transport", forKey: TransportSettings.transportDefaultsKey)
+    #expect(TransportSettings.transport(defaults: suite.defaults) == .airDrop)
+}
+
+@Test
+func oneDriveFolderStoreAndReset() throws {
+    let suite = try makeTransportDefaultsSuite()
+    defer { tearDownTransportSuite(suite) }
+    let folder = try makeTransportTemporaryDirectory(prefix: "shotdeck-onedrive-folder")
+    defer { try? FileManager.default.removeItem(at: folder) }
+
+    #expect(TransportSettings.storedOneDriveFolderPath(defaults: suite.defaults) == nil)
+
+    TransportSettings.setOneDriveFolder(folder, defaults: suite.defaults)
+    #expect(TransportSettings.storedOneDriveFolderPath(defaults: suite.defaults) == folder.path)
+
+    TransportSettings.resetOneDriveFolder(defaults: suite.defaults)
+    #expect(TransportSettings.storedOneDriveFolderPath(defaults: suite.defaults) == nil)
+}
+
+@Test
+func effectiveFoldersForAirDropMatchesFolderSettings() throws {
+    let suite = try makeTransportDefaultsSuite()
+    defer { tearDownTransportSuite(suite) }
+    let outbox = try makeTransportTemporaryDirectory(prefix: "shotdeck-effective-outbox")
+    defer { try? FileManager.default.removeItem(at: outbox) }
+    FolderSettings.setOutbox(outbox, defaults: suite.defaults)
+
+    let effective = TransportSettings.effectiveFolders(defaults: suite.defaults)
+    let expected = FolderSettings.resolve(defaults: suite.defaults)
+
+    #expect(effective.transport == .airDrop)
+    #expect(effective.outbox.path == expected.outbox.path)
+    #expect(effective.watch.path == expected.watch.path)
+}
+
+@Test
+func effectiveFoldersForOneDriveWithAResolvableFolderUsesItForBoth() throws {
+    let suite = try makeTransportDefaultsSuite()
+    defer { tearDownTransportSuite(suite) }
+    let folder = try makeTransportTemporaryDirectory(prefix: "shotdeck-effective-onedrive")
+    defer { try? FileManager.default.removeItem(at: folder) }
+
+    TransportSettings.setTransport(.oneDrive, defaults: suite.defaults)
+    TransportSettings.setOneDriveFolder(folder, defaults: suite.defaults)
+
+    let effective = TransportSettings.effectiveFolders(defaults: suite.defaults)
+
+    #expect(effective.transport == .oneDrive)
+    #expect(effective.outbox.path == folder.path)
+    #expect(effective.watch.path == folder.path)
+    #expect(effective.outbox.path == effective.watch.path)
+}
+
+@Test
+func oneDriveFolderUnavailableErrorDescriptionContainsThePath() throws {
+    let path = "/Users/example/Library/CloudStorage/OneDrive-Example/Redline"
+    let error = ShotdeckError.oneDriveFolderUnavailable(path: path)
+    let description = try #require(error.errorDescription)
+    #expect(!description.isEmpty)
+    #expect(description.contains(path))
+}
+
+@Test
+func isWritableDirectoryTrueForAnOrdinaryWritableDirectory() throws {
+    let dir = try makeTransportTemporaryDirectory(prefix: "shotdeck-writable")
+    defer { try? FileManager.default.removeItem(at: dir) }
+    #expect(OneDriveLocator.isWritableDirectory(at: dir))
+}
+
+@Test
+func isWritableDirectoryFalseForAnExistingButUnwritableDirectory() throws {
+    let dir = try makeTransportTemporaryDirectory(prefix: "shotdeck-unwritable")
+    defer {
+        // Restore perms BEFORE removal — an unwritable dir can't otherwise be cleaned up.
+        try? FileManager.default.setAttributes([.posixPermissions: 0o755], ofItemAtPath: dir.path)
+        try? FileManager.default.removeItem(at: dir)
+    }
+    #expect(OneDriveLocator.isWritableDirectory(at: dir))   // sanity check before chmod
+
+    try FileManager.default.setAttributes([.posixPermissions: 0o500], ofItemAtPath: dir.path)
+    #expect(!OneDriveLocator.isWritableDirectory(at: dir))
+}
+
+@Test
+func isWritableDirectoryFalseForAPlainFileAndForANonexistentPath() throws {
+    let dir = try makeTransportTemporaryDirectory(prefix: "shotdeck-writable-check-parent")
+    defer { try? FileManager.default.removeItem(at: dir) }
+    let filePath = dir.appendingPathComponent("plain-file.txt")
+    FileManager.default.createFile(atPath: filePath.path, contents: Data("x".utf8))
+
+    #expect(!OneDriveLocator.isWritableDirectory(at: filePath))
+    #expect(!OneDriveLocator.isWritableDirectory(at: dir.appendingPathComponent("does-not-exist")))
+}
+
+@Test
+func probeWritableTrueForAnOrdinaryWritableDirectoryAndLeavesNoProbeFileBehind() throws {
+    let dir = try makeTransportTemporaryDirectory(prefix: "shotdeck-probe-writable")
+    defer { try? FileManager.default.removeItem(at: dir) }
+
+    #expect(OneDriveLocator.probeWritable(at: dir))
+
+    let leftovers = try FileManager.default.contentsOfDirectory(atPath: dir.path)
+    #expect(leftovers.isEmpty)
+}
+
+@Test
+func probeWritableFalseForAChmod500Directory() throws {
+    // The File Provider edge case this probe exists for: isWritableDirectory can be
+    // true (as verified by the isWritableDirectory tests above) while an actual write
+    // still fails. A chmod 500 directory reproduces that "looks writable, isn't"
+    // shape closely enough to prove the probe itself does a real write, not just
+    // another permissions-bit check.
+    let dir = try makeTransportTemporaryDirectory(prefix: "shotdeck-probe-unwritable")
+    defer {
+        try? FileManager.default.setAttributes([.posixPermissions: 0o755], ofItemAtPath: dir.path)
+        try? FileManager.default.removeItem(at: dir)
+    }
+    try FileManager.default.setAttributes([.posixPermissions: 0o500], ofItemAtPath: dir.path)
+
+    #expect(!OneDriveLocator.probeWritable(at: dir))
+}
+
+@Test
+func probeWritableFalseForAPlainFilePath() throws {
+    let dir = try makeTransportTemporaryDirectory(prefix: "shotdeck-probe-file-parent")
+    defer { try? FileManager.default.removeItem(at: dir) }
+    let filePath = dir.appendingPathComponent("plain-file.txt")
+    FileManager.default.createFile(atPath: filePath.path, contents: Data("x".utf8))
+
+    #expect(!OneDriveLocator.probeWritable(at: filePath))
+}
+
+/// The write itself succeeds (a real probe file lands on disk via AtomicFile.write,
+/// which never touches this injected FileManager — it uses raw POSIX calls), but the
+/// FIRST call to `removeItem(at:)` throws, simulating a transient File Provider
+/// removal failure. probeWritable's own defer-based cleanup must retry and succeed
+/// (the second call through this same override falls through to `super`), so no
+/// probe file is left behind even though the function correctly still reports false
+/// (the removal it explicitly attempted did fail).
+private final class ThrowOnceOnRemoveFileManager: FileManager, @unchecked Sendable {
+    private let lock = NSLock()
+    private var hasThrown = false
+
+    override func removeItem(at URL: URL) throws {
+        lock.lock()
+        let shouldThrow = !hasThrown
+        hasThrown = true
+        lock.unlock()
+        if shouldThrow {
+            throw NSError(domain: "ShotdeckCoreTests.ThrowOnceOnRemove", code: 1)
+        }
+        try super.removeItem(at: URL)
+    }
+}
+
+@Test
+func probeWritableFalseAndLeavesNoProbeFileWhenRemoveItemThrowsOnce() throws {
+    // Directory fsync failure (the OTHER way probeWritable's cleanup can be needed) has
+    // no injectable seam: AtomicFile.write's directory fsync is a raw Darwin fsync(2)
+    // call on an already-open file descriptor, not parameterized by any FileManager or
+    // other dependency this test can substitute, and there is no portable way to make
+    // fsync(2) itself fail via chmod or other standard test techniques (fsync failures
+    // are OS/filesystem/hardware-level events). Covering the removeItem-throws path
+    // (below) is what this test does; the fsync-throws path is covered by code
+    // inspection only — the same `defer` block guards both.
+    let dir = try makeTransportTemporaryDirectory(prefix: "shotdeck-probe-remove-throws")
+    defer { try? FileManager.default.removeItem(at: dir) }
+    let injectedFileManager = ThrowOnceOnRemoveFileManager()
+
+    #expect(!OneDriveLocator.probeWritable(at: dir, fileManager: injectedFileManager))
+
+    let leftovers = try FileManager.default.contentsOfDirectory(atPath: dir.path)
+    #expect(leftovers.isEmpty)
+}
+
+struct TransportDefaultsSuite {
+    let name: String
+    let defaults: UserDefaults
+}
+
+func makeTransportDefaultsSuite() throws -> TransportDefaultsSuite {
+    let name = "shotdeck-transport-test-\(UUID().uuidString)"
+    let defaults = try #require(UserDefaults(suiteName: name))
+    defaults.removePersistentDomain(forName: name)
+    return TransportDefaultsSuite(name: name, defaults: defaults)
+}
+
+func tearDownTransportSuite(_ suite: TransportDefaultsSuite) {
+    suite.defaults.removePersistentDomain(forName: suite.name)
+}
+
+func makeTransportTemporaryDirectory(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
+}

Tests/ShotdeckTests/LaunchWiringTests.swift

@@ -0,0 +1,142 @@
+import AppKit
+import Foundation
+import PDFKit
+import Testing
+import ShotdeckCore
+@testable import Shotdeck
+
+/// Coverage gap closed (adversarial review, rounds 3 and 4): the Core-level regression
+/// tests in ShotdeckCoreTests hand-replicate what `AppDelegate.makeLaunchModel()` and
+/// `AppModel.bootstrap()` do, rather than calling them — so a future revert of
+/// `makeLaunchModel()` back to the AirDrop-only resolver, or a dropped
+/// `updateWatchFolder` call inside `bootstrap()`, would NOT fail `swift test`. This
+/// test goes through the real, unmodified call sites in the `Shotdeck` executable
+/// target via `@testable import`, which `ShotdeckCoreTests` cannot reach (it only
+/// depends on `ShotdeckCore`) — hence this separate `ShotdeckTests` target.
+///
+/// Round 4 correction: the first version of this test asserted only
+/// `model.watchFolderURL`, which `AppModel.init` computes independently via
+/// `TransportSettings.effectiveFolders()` — so it stayed correct (and the test kept
+/// passing) even when `makeLaunchModel()` was reverted to the AirDrop-only resolver,
+/// because `bootstrap()`'s own unconditional `updateWatchFolder` reconcile papered
+/// over the reverted resolver. That made the "verified this catches the blocker"
+/// claim in the previous round's commit message empirically false. This version
+/// asserts `model.paths`/the watcher's `currentWatchFolder` BEFORE `bootstrap()` runs,
+/// which actually depends on what `makeLaunchModel()` built — see this file's git
+/// history (or the round-4 commit message) for the verbatim before/after
+/// `swift test --filter` output proving it now discriminates correctly.
+@MainActor
+@Test("Real wiring: AppDelegate.makeLaunchModel() + AppModel.bootstrap() detect a marked OneDrive return")
+func realLaunchModelAndBootstrapDetectAMarkedOneDriveReturn() async throws {
+    let fm = FileManager.default
+
+    // UserDefaults.standard is the ONLY defaults instance makeLaunchModel()/bootstrap()
+    // actually read — there is no defaults-threading through AppModel/AppDelegate (the
+    // same reasoning documented in PickerSelfTest.swift's ONEDRIVE-SELFTEST phase).
+    // "Isolated" here means snapshot-and-restore around the real keys, not a separate
+    // UserDefaults(suiteName:) instance that these real, unmodified call sites would
+    // never actually consult.
+    let defaults = UserDefaults.standard
+    let previousTransport = defaults.string(forKey: TransportSettings.transportDefaultsKey)
+    let previousFolder = defaults.string(forKey: TransportSettings.oneDriveFolderDefaultsKey)
+    defer {
+        if let previousTransport {
+            defaults.set(previousTransport, forKey: TransportSettings.transportDefaultsKey)
+        } else {
+            defaults.removeObject(forKey: TransportSettings.transportDefaultsKey)
+        }
+        if let previousFolder {
+            defaults.set(previousFolder, forKey: TransportSettings.oneDriveFolderDefaultsKey)
+        } else {
+            defaults.removeObject(forKey: TransportSettings.oneDriveFolderDefaultsKey)
+        }
+    }
+
+    let oneDriveFolderRaw = fm.temporaryDirectory
+        .appendingPathComponent("shotdeck-real-wiring-onedrive-\(UUID().uuidString)", isDirectory: true)
+    try fm.createDirectory(at: oneDriveFolderRaw, withIntermediateDirectories: true)
+    defer { try? fm.removeItem(at: oneDriveFolderRaw) }
+    // FileManager's directory enumeration (inside the real ReturnWatcher/AppSupportPaths
+    // call sites this test exercises) can canonicalize /var -> /private/var for a path
+    // that actually exists; resolve here so every comparison below agrees.
+    let oneDriveFolder = oneDriveFolderRaw.resolvingSymlinksInPath()
+
+    let appSupportRoot = fm.temporaryDirectory
+        .appendingPathComponent("shotdeck-real-wiring-approot-\(UUID().uuidString)", isDirectory: true)
+    defer { try? fm.removeItem(at: appSupportRoot) }
+
+    TransportSettings.setTransport(.oneDrive, defaults: defaults)
+    TransportSettings.setOneDriveFolder(oneDriveFolder, defaults: defaults)
+
+    // Best-effort: keeps AppModel.bootstrap()'s real update-check schedule (a real
+    // HTTP GET after 10s, plus a RunLoop timer) from starting during this test.
+    // ProcessInfo.processInfo.environment on Darwin reads `environ` fresh each call,
+    // so a setenv() here is visible to bootstrap()'s own check immediately.
+    setenv("SHOTDECK_ONEDRIVE_SELFTEST", "1", 1)
+    defer { unsetenv("SHOTDECK_ONEDRIVE_SELFTEST") }
+
+    // The REAL, unmodified call sites — not a reimplementation. This is exactly what
+    // launching Redline with OneDrive as the persisted transport does.
+    let model = AppDelegate.makeLaunchModel(appSupportRoot: appSupportRoot)
+    // bootstrap() registers a REAL, process-wide Carbon global hotkey (capture combo,
+    // e.g. Option-Shift-2). Carbon registrations are not scoped to this test/model —
+    // they must be released before this test ends, or ShotdeckCoreTests'
+    // HotkeyCenterCarbonTests (a separate test target, same test process) can find the
+    // combo already taken / the global hotkey table in an unexpected state.
+    defer { model.hotkeys.unregisterAll() }
+
+    // PRE-bootstrap assertions — this is the actual proof of the launch RESOLVER
+    // (AppDelegate.makeLaunchModel() -> TransportSettings.resolvedAppSupportPaths()),
+    // independent of bootstrap()'s own reconcile. `model.watchFolderURL` alone does
+    // NOT prove this: AppModel.init computes it separately via
+    // TransportSettings.effectiveFolders(), so it would read as correct even if
+    // makeLaunchModel's `paths` were built by the AirDrop-only resolver — which is
+    // exactly how the first version of this test was empirically shown to be vacuous
+    // for the launch-resolver path (see this commit's message). `model.paths` is
+    // `internal` on AppModel, so @testable import already exposes it without any
+    // production API change; `currentWatchFolder` is the one new (internal-facing,
+    // `public` on the actor) seam added to ReturnWatcher for this purpose.
+    #expect(model.paths.watchFolder.path == oneDriveFolder.path)
+    #expect(model.paths.outbox.path == oneDriveFolder.path)
+    let seededWatchFolder = await model.watcher.currentWatchFolder
+    #expect(seededWatchFolder.path == oneDriveFolder.path)
+
+    #expect(model.transport == .oneDrive)
+    #expect(model.watchFolderURL.path == oneDriveFolder.path)
+
+    await model.bootstrap()
+
+    // Drop a marked-up Redline PDF into the folder in place — what OneDrive syncing
+    // down an already-marked copy after a relaunch looks like.
+    let pdfURL = oneDriveFolder.appendingPathComponent("Redline-realwiring-\(UUID().uuidString).pdf")
+    let document = PDFDocument()
+    let page = PDFPage()
+    page.setBounds(CGRect(x: 0, y: 0, width: 612, height: 792), for: .mediaBox)
+    document.insert(page, at: 0)
+    document.documentAttributes = [
+        PDFDocumentAttribute.creatorAttribute: "Redline",
+        PDFDocumentAttribute.subjectAttribute: UUID().uuidString,
+    ]
+    let ink = PDFAnnotation(
+        bounds: CGRect(x: 20, y: 20, width: 60, height: 60), forType: .ink, withProperties: nil
+    )
+    let stroke = NSBezierPath()
+    stroke.move(to: NSPoint(x: 20, y: 20))
+    stroke.line(to: NSPoint(x: 80, y: 80))
+    ink.add(stroke)
+    page.addAnnotation(ink)
+    let written = document.write(to: pdfURL)
+    #expect(written)
+    guard written else { return }
+
+    // .resolvingSymlinksInPath().path — not plain URL equality — matching how the rest
+    // of the suite compares a temp-dir-derived expected URL against a returned one.
+    let expectedPath = pdfURL.resolvingSymlinksInPath().path
+    let found = try await model.watcher.scanNow()
+    #expect(found.first(where: { $0.fileURL.resolvingSymlinksInPath().path == expectedPath })?.isCommented == true)
+
+    let commented = try await model.ledger.commented()
+    #expect(commented.contains(where: { $0.fileURL.resolvingSymlinksInPath().path == expectedPath }))
+
+    await model.watcher.stop()
+}

Tests/ShotdeckTests/UpdateCheckerTests.swift

@@ -0,0 +1,118 @@
+import Foundation
+import Testing
+@testable import Shotdeck
+@testable import ShotdeckCore
+
+@Test("DubaiTime.checkTime formats as HH:MM Dubai")
+func dubaiTimeCheckTimeFormat() {
+    let now = Date()
+    let result = DubaiTime.checkTime(now)
+
+    // Dubai timezone format: HH:MM Dubai
+    let pattern = "^[0-9]{2}:[0-9]{2} Dubai$"
+    let regex = try? NSRegularExpression(pattern: pattern, options: [])
+    let range = NSRange(result.startIndex..<result.endIndex, in: result)
+    let matches = regex?.matches(in: result, options: [], range: range) ?? []
+    #expect(!matches.isEmpty, "checkTime should format as HH:MM Dubai, got: \(result)")
+}
+
+@Test("Status message: up-to-date manual check includes Dubai timestamp")
+@MainActor
+func manualCheckUpToDateIncludesTimestamp() async {
+    let checker = UpdateChecker()
+
+    // Inject a stub appcast showing the current version (no update available)
+    let currentVersion = UpdateChecker.currentVersion()
+    let stubAppcast = """
+    {
+      "version": "\(currentVersion)",
+      "zipURL": "https://example.com/dummy.zip",
+      "sha256": "0000000000000000000000000000000000000000000000000000000000000000"
+    }
+    """
+    checker.testAppcastJSON = stubAppcast
+
+    // Capture the status message
+    var capturedStatus: String?
+    checker.onChecked = {
+        capturedStatus = checker.statusMessage
+    }
+
+    // Run the manual check
+    await checker.checkNow(manual: true)
+
+    // Verify the message matches the expected format and includes a timestamp
+    guard let status = capturedStatus else {
+        #expect(false, "statusMessage should not be nil for manual check finding no update")
+        return
+    }
+
+    // Message should be "Redline X.Y.Z is up to date, checked HH:MM Dubai"
+    let pattern = "^Redline [0-9]+\\.[0-9]+\\.[0-9]+ is up to date, checked [0-9]{2}:[0-9]{2} Dubai$"
+    let regex = try? NSRegularExpression(pattern: pattern, options: [])
+    let range = NSRange(status.startIndex..<status.endIndex, in: status)
+    let matches = regex?.matches(in: status, options: [], range: range) ?? []
+    #expect(!matches.isEmpty, "Manual check up-to-date message should match format, got: \(status)")
+}
+
+@Test("Status message: automatic check doesn't set message when up-to-date")
+@MainActor
+func automaticCheckUpToDateLeavesMessageNil() async {
+    let checker = UpdateChecker()
+
+    // Inject a stub appcast showing the current version (no update available)
+    let currentVersion = UpdateChecker.currentVersion()
+    let stubAppcast = """
+    {
+      "version": "\(currentVersion)",
+      "zipURL": "https://example.com/dummy.zip",
+      "sha256": "0000000000000000000000000000000000000000000000000000000000000000"
+    }
+    """
+    checker.testAppcastJSON = stubAppcast
+
+    // Capture the status message
+    var capturedStatus: String?
+    checker.onChecked = {
+        capturedStatus = checker.statusMessage
+    }
+
+    // Run an AUTOMATIC check (manual: false)
+    await checker.checkNow(manual: false)
+
+    // For automatic checks finding no update, statusMessage should be nil
+    #expect(capturedStatus == nil,
+            "Automatic check finding no update should leave statusMessage nil, got: \(capturedStatus ?? "(nil)")")
+}
+
+@Test("Update status and general status are independent channels")
+@MainActor
+func statusChannelsAreIndependent() async throws {
+    let fm = FileManager.default
+    let appSupportRoot = fm.temporaryDirectory
+        .appendingPathComponent("update-checker-channel-test-\(UUID().uuidString)", isDirectory: true)
+    defer { try? fm.removeItem(at: appSupportRoot) }
+
+    // Create a real AppModel using the standard launch pattern
+    let model = AppDelegate.makeLaunchModel(appSupportRoot: appSupportRoot)
+    defer { model.hotkeys.unregisterAll() }
+
+    // Test 1: Setting statusLine should NOT affect updateStatusMessage
+    model.setStatus("General status: captured 3")
+    #expect(model.statusLine == "General status: captured 3", "statusLine should be set")
+    #expect(model.updateStatusMessage == nil, "updateStatusMessage should remain nil")
+
+    // Test 2: Setting updateStatus should NOT affect statusLine
+    model.setUpdateStatus("Update to 9.9.9 is ready")
+    #expect(model.statusLine == "General status: captured 3", "statusLine should remain unchanged")
+    #expect(model.updateStatusMessage == "Update to 9.9.9 is ready", "updateStatusMessage should be set")
+
+    // Test 3: Clearing statusLine leaves updateStatus intact
+    model.setStatus(nil)
+    #expect(model.statusLine == nil, "statusLine should be cleared")
+    #expect(model.updateStatusMessage == "Update to 9.9.9 is ready", "updateStatusMessage should persist")
+
+    // Test 4: Clearing updateStatus leaves other state unaffected
+    model.setUpdateStatus(nil)
+    #expect(model.updateStatusMessage == nil, "updateStatusMessage should be cleared")
+}