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/test/core/notification_permission_test.dart

@@ -0,0 +1,80 @@
+/// POST_NOTIFICATIONS 权限门测试（P3 计划 Task 9）。
+///
+/// 覆盖：Android 首次请求一次（幂等，二次调用不触通道）、非 Android 跳过、
+/// 通道缺失/异常静默降级不阻断入队。
+library;
+
+import 'package:flutter/services.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:photo_live/core/notification_permission.dart';
+
+void main() {
+  TestWidgetsFlutterBinding.ensureInitialized();
+
+  const channel = MethodChannel(NotificationPermission.kChannelName);
+  // 测试绑定的 defaultBinaryMessenger 即 TestDefaultBinaryMessenger
+  // （setMockMethodCallHandler 所在）。
+  final byteData = TestWidgetsFlutterBinding.instance.defaultBinaryMessenger;
+
+  tearDown(() => byteData.setMockMethodCallHandler(channel, null));
+
+  test('Android：首次请求触发通道一次；再次调用不再打扰（幂等）', () async {
+    var calls = 0;
+    byteData.setMockMethodCallHandler(channel, (call) async {
+      expect(call.method, 'requestPostNotifications');
+      calls++;
+      return 'granted';
+    });
+    final permission =
+        NotificationPermission(isAndroid: true, channel: channel);
+
+    await permission.ensureRequested();
+    await permission.ensureRequested();
+    await permission.ensureRequested();
+
+    expect(calls, 1, reason: '进程内只请求一次');
+  });
+
+  test('非 Android：不触通道（iOS 后台传输不依赖通知权限）', () async {
+    var calls = 0;
+    byteData.setMockMethodCallHandler(channel, (call) async {
+      calls++;
+      return 'granted';
+    });
+    final permission =
+        NotificationPermission(isAndroid: false, channel: channel);
+
+    await permission.ensureRequested();
+
+    expect(calls, 0);
+  });
+
+  test('通道缺失（iOS/桌面无此方法）→ 静默降级不抛', () async {
+    byteData.setMockMethodCallHandler(
+      channel,
+      (call) async => throw MissingPluginException('no handler'),
+    );
+    final permission =
+        NotificationPermission(isAndroid: true, channel: channel);
+
+    await permission.ensureRequested(); // 不抛即通过。
+  });
+
+  test('通道异常后仍标记已请求（失败也不二次打扰）', () async {
+    var calls = 0;
+    byteData.setMockMethodCallHandler(
+      channel,
+      (call) async {
+        calls++;
+        throw PlatformException(code: 'ACTIVITY_MISSING');
+      },
+    );
+    final permission =
+        NotificationPermission(isAndroid: true, channel: channel);
+
+    await permission.ensureRequested();
+    await permission.ensureRequested();
+
+    expect(calls, 1);
+  });
+}