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/features/uploads/providers.dart

@@ -2,10 +2,12 @@
 ///
 /// 生产装配：TaskStore.app()（documents/upload_tasks.sqlite）+ ApiClient
 /// （Bearer 自动注入）+ DeviceId（shared_preferences）。引擎生命周期
-/// （start(accountId)/stop，随登录态切换）由 App 壳/队列 UI 驱动——
-/// Task 9 队列 UI 落地时接线；本文件保证依赖图就绪。
+/// （start(accountId)/stop，随登录态切换）在 engine_scope.dart 绑定
+/// （Task 9 接线）。
 library;
 
+import 'dart:async';
+
 import 'package:flutter_riverpod/flutter_riverpod.dart';
 
 import '../../core/api_client.dart';
@@ -21,13 +23,55 @@ final taskStoreProvider = Provider<TaskStore>((ref) {
   return store;
 });
 
+/// 单任务传输进度事件（队列 UI 行级进度条消费）。
+class UploadTaskProgress {
+  const UploadTaskProgress({
+    required this.taskId,
+    required this.sent,
+    required this.total,
+  });
+
+  final String taskId;
+  final int sent;
+  final int total;
+
+  /// 0~1 进度分数；total 未知（0）返回 null（UI 转不确定态进度条）。
+  double? get fraction =>
+      total > 0 ? (sent / total).clamp(0.0, 1.0).toDouble() : null;
+}
+
+/// 进度事件总线：引擎 onProgress 回调 → 广播流（行级 StreamBuilder 按
+/// taskId 过滤消费，避免整表重建风暴）。
+class UploadProgressHub {
+  final StreamController<UploadTaskProgress> _controller =
+      StreamController<UploadTaskProgress>.broadcast();
+
+  /// 进度事件流（广播；行级按 taskId 过滤）。
+  Stream<UploadTaskProgress> get stream => _controller.stream;
+
+  /// 引擎回调挂接点（uploadEngineProvider 内接线）。
+  void emit(String taskId, int sent, int total) =>
+      _controller.add(UploadTaskProgress(taskId: taskId, sent: sent, total: total));
+
+  void dispose() => _controller.close();
+}
+
+/// 进度总线 Provider。
+final uploadProgressHubProvider = Provider<UploadProgressHub>((ref) {
+  final hub = UploadProgressHub();
+  ref.onDispose(hub.dispose);
+  return hub;
+});
+
 /// 传输引擎（裸 Dio 直传 presign；并行/保留期配置见 upload_engine.dart
-/// 的 dart-define 常量）。
+/// 的 dart-define 常量；进度经 [UploadProgressHub] 广播）。
 final uploadEngineProvider = Provider<UploadEngine>((ref) {
+  final hub = ref.watch(uploadProgressHubProvider);
   final engine = UploadEngine(
     ref.watch(taskStoreProvider),
     ref.watch(apiClientProvider),
     ref.watch(deviceIdProvider),
+    onProgress: (taskId, sent, total) => hub.emit(taskId, sent, total),
   );
   ref.onDispose(engine.dispose);
   return engine;