提交 Nontonki 短剧原型，准备推送到远程仓库。

Co-authored-by: Cursor <cursoragent@cursor.com>

test/engagement/engagement_controller_test.dart

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+import 'package:flutter_test/flutter_test.dart';
+import 'package:nontonki/core/data/services/engagement_controller.dart';
+import 'package:nontonki/core/data/repositories/engagement_repository.dart';
+import 'package:shared_preferences_platform_interface/in_memory_shared_preferences_async.dart';
+import 'package:shared_preferences_platform_interface/shared_preferences_async_platform_interface.dart';
+
+void main() {
+  test('saved, liked and comments are kept by drama id', () async {
+    final repository = InMemoryEngagementRepository();
+    final first = EngagementController(repository);
+    await first.load();
+    await first.toggleSaved('signal');
+    await first.toggleLiked('signal');
+    await first.addComment('signal', '  Great clip  ');
+
+    expect(first.isSaved('signal'), isTrue);
+    expect(first.isSaved('city'), isFalse);
+    expect(first.isLiked('city'), isFalse);
+    expect(first.commentsFor('signal'), ['Great clip']);
+    expect(first.commentsFor('city'), isEmpty);
+
+    final reopened = EngagementController(repository);
+    await reopened.load();
+    expect(reopened.isSaved('signal'), isTrue);
+    expect(reopened.isLiked('signal'), isTrue);
+    expect(reopened.commentsFor('signal'), ['Great clip']);
+    await reopened.toggleSaved('signal');
+    expect(reopened.isSaved('signal'), isFalse);
+  });
+
+  test('local engagement survives a new repository instance', () async {
+    SharedPreferencesAsyncPlatform.instance =
+        InMemorySharedPreferencesAsync.empty();
+    final first = EngagementController(SharedPreferencesEngagementRepository());
+    await first.load();
+    await first.toggleSaved('city');
+    await first.addComment('city', 'Local note');
+
+    final reopened = EngagementController(
+      SharedPreferencesEngagementRepository(),
+    );
+    await reopened.load();
+    expect(reopened.isSaved('city'), isTrue);
+    expect(reopened.commentsFor('city'), ['Local note']);
+  });
+}