feat(mobile): upload queue ui and continuous capture page

Task 9 (P3 plan): queue tab replaces the stub, continuous capture page
enqueues per shot, album detail gains an upload FAB, and the upload
engine lifecycle is now bound to the login session.

- Engine scope: session account drives UploadEngine start/stop; wired
  from app boot, login success, logout, and 401 eviction. Tasks stay in
  the store across logout (accountId hard isolation).
- Queue tab: album x state x time filter bar, task rows with thumbnail,
  state chip, localized error copy, attempt count, per-row progress via
  a broadcast progress hub, state-dependent actions (re-pick retry,
  retryNow, cancel, delete), batch retry bar, 200ms-debounced live
  refresh from drift table updates.
- Capture page: camera preview via injected CaptureSource, one enqueue
  per shutter press, persistent album/category/badges overlay with a
  switch-only-affects-new-shots hint, gallery multi-pick, exit confirm
  while uploads are pending, permission-denied and init-failure views.
- POST_NOTIFICATIONS runtime permission via a small MethodChannel
  (photolive/permissions) + PermissionPlugin.kt: single runtime
  permission need, avoids permission_handler dependency; requested once
  on first enqueue, silent degradation when denied or unavailable.
- Album detail FAB: capture-and-upload / pick-from-gallery sheet.
- l10n: ~50 new keys in zh/en arbs; tests: +45 (filter matrix, engine
  scope lifecycle, permission gate, queue tab, capture page, FAB entry);
  existing page tests updated to inject session/task-store fakes.

Co-Authored-By: Claude Code <noreply@anthropic.com>

apps/mobile/lib/l10n/app_localizations_en.dart

@@ -370,4 +370,171 @@ class AppLocalizationsEn extends AppLocalizations {
 
   @override
   String get thisDevice => 'This device';
+
+  @override
+  String get queueAlbumFilterAll => 'All albums';
+
+  @override
+  String get queueStateAll => 'All';
+
+  @override
+  String get queueStatePreparing => 'Preparing';
+
+  @override
+  String get queueStateQueued => 'Queued';
+
+  @override
+  String get queueStateUploading => 'Uploading';
+
+  @override
+  String get queueStateWaitingNetwork => 'Waiting for network';
+
+  @override
+  String get queueStateFailed => 'Failed';
+
+  @override
+  String get queueStateCompleted => 'Done';
+
+  @override
+  String get queueTimeAll => 'Any time';
+
+  @override
+  String get queueTimeToday => 'Today';
+
+  @override
+  String get queueTimeLast7Days => 'Last 7 days';
+
+  @override
+  String get queueTimeLast30Days => 'Last 30 days';
+
+  @override
+  String get queueEmpty => 'No upload tasks';
+
+  @override
+  String get queueRetryAllFailed => 'Retry all failed';
+
+  @override
+  String queueAttemptCount(int count) {
+    return '$count attempt(s)';
+  }
+
+  @override
+  String get taskStatePreparing => 'Preparing';
+
+  @override
+  String get taskStatePreparationFailed => 'Preparation failed';
+
+  @override
+  String get taskStateQueued => 'Queued';
+
+  @override
+  String get taskStateUploading => 'Uploading';
+
+  @override
+  String get taskStateUploadedConfirming => 'Confirming';
+
+  @override
+  String get taskStateCompleted => 'Completed';
+
+  @override
+  String get taskStateWaitingNetwork => 'Waiting for network';
+
+  @override
+  String get taskStateRetryableFailed => 'Upload failed';
+
+  @override
+  String get taskStateCancelled => 'Cancelled';
+
+  @override
+  String get errorPrepSourceUnreadable =>
+      'Could not read the selected photo. Please reselect';
+
+  @override
+  String get errorPrepUnsupportedType =>
+      'Only JPG, PNG and HEIC images are supported';
+
+  @override
+  String get errorPrepTooLarge => 'Photo exceeds the 50MB limit';
+
+  @override
+  String get errorPrepCopyFailed => 'Failed to copy the photo. Please retry';
+
+  @override
+  String get errorUploadSourceMissing =>
+      'Source file is missing. Please reselect';
+
+  @override
+  String get errorAlbumUploadDisabled => 'Album uploads are disabled';
+
+  @override
+  String get errorUploadSessionConflict =>
+      'Upload session conflict. Please retry';
+
+  @override
+  String get errorUploadVerifyFailed =>
+      'Upload verification failed. Will retry';
+
+  @override
+  String get captureTitle => 'Continuous capture';
+
+  @override
+  String get captureCategoryDefault => 'Default category';
+
+  @override
+  String get captureSwitchHint =>
+      'Switching only affects photos captured afterwards';
+
+  @override
+  String capturePendingBadge(int count) {
+    return 'Pending $count';
+  }
+
+  @override
+  String captureFailedBadge(int count) {
+    return 'Failed $count';
+  }
+
+  @override
+  String get capturePickFromGallery => 'Pick from gallery';
+
+  @override
+  String get captureShutter => 'Capture';
+
+  @override
+  String get captureExitTitle => 'Leave shooting?';
+
+  @override
+  String captureExitBody(int count) {
+    return '$count photo(s) are still uploading. Tasks will continue in the background after you leave.';
+  }
+
+  @override
+  String get captureKeepShooting => 'Keep shooting';
+
+  @override
+  String get captureExitConfirm => 'Leave';
+
+  @override
+  String get cameraPermissionDenied =>
+      'Camera unavailable. Allow camera access in system settings';
+
+  @override
+  String get cameraInitFailed => 'Camera failed to initialize';
+
+  @override
+  String get uploadActionCapture => 'Capture and upload';
+
+  @override
+  String get uploadActionPick => 'Pick from gallery';
+
+  @override
+  String get uploadAction => 'Upload';
+
+  @override
+  String uploadEnqueuedCount(int count) {
+    return 'Added $count photo(s) to the upload queue';
+  }
+
+  @override
+  String get uploadPickNone => 'No photos selected';
 }