feat: A3 数据层 AppCatalogController（feed/详情/分类加载，供页面切换）

lib/app.dart

@@ -7,7 +7,9 @@ import 'core/config/locale_controller.dart';
 import 'core/data/repositories/auth_repository.dart';
 import 'core/data/repositories/catalog_repository.dart';
 import 'core/data/repositories/engagement_repository.dart';
+import 'core/data/repositories/http_catalog_repository.dart';
 import 'core/data/services/api_client.dart';
+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';
@@ -39,6 +41,12 @@ class LumaDramaApp extends StatelessWidget {
         ChangeNotifierProvider(
           create: (ctx) => AuthController(ctx.read<AuthRepository>()),
         ),
+        Provider(
+          create: (ctx) => HttpCatalogRepository(ctx.read<ApiClient>()),
+        ),
+        ChangeNotifierProvider(
+          create: (ctx) => AppCatalogController(ctx.read<HttpCatalogRepository>()),
+        ),
         ChangeNotifierProvider(
           create: (_) => CatalogController(DemoCatalogRepository())..load(),
         ),