feat: C3 客户端埋点 SDK（EventTracker 批量上报 + 核心事件）

lib/app.dart

@@ -13,6 +13,7 @@ import 'core/data/services/app_catalog_controller.dart';
 import 'core/data/services/auth_controller.dart';
 import 'core/data/services/catalog_controller.dart';
 import 'core/data/services/engagement_controller.dart';
+import 'core/data/services/event_tracker.dart';
 import 'core/data/services/playback_session.dart';
 import 'core/data/services/token_storage.dart';
 import 'core/data/services/video_player_port.dart';
@@ -31,6 +32,7 @@ class LumaDramaApp extends StatelessWidget {
         Provider(create: (_) => PlaybackCoordinator()),
         Provider<PlayerFactory>(create: (_) => playerFactory),
         Provider(create: (_) => ApiClient()),
+        Provider(create: (ctx) => EventTracker(ctx.read<ApiClient>())),
         Provider(create: (_) => TokenStorage()),
         Provider(
           create: (ctx) => AuthRepository(