提交 Nontonki 短剧原型，准备推送到远程仓库。

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

test/playback/watch_history_test.dart

@@ -0,0 +1,54 @@
+import 'package:flutter_test/flutter_test.dart';
+import 'package:nontonki/core/data/repositories/watch_history_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('resume position clamps invalid and completed values', () {
+    const duration = Duration(seconds: 8);
+    expect(
+      clampResumePosition(const Duration(seconds: -1), duration),
+      Duration.zero,
+    );
+    expect(
+      clampResumePosition(const Duration(seconds: 3), duration),
+      const Duration(seconds: 3),
+    );
+    expect(
+      clampResumePosition(const Duration(seconds: 9), duration),
+      Duration.zero,
+    );
+    expect(
+      clampResumePosition(const Duration(milliseconds: 7700), duration),
+      Duration.zero,
+    );
+  });
+
+  test('watch history is scoped by profile, drama and episode', () async {
+    SharedPreferencesAsyncPlatform.instance =
+        InMemorySharedPreferencesAsync.empty();
+    final history = SharedPreferencesWatchHistoryRepository();
+    await history.save(
+      'profile-a',
+      'drama-a',
+      'episode-1',
+      const Duration(seconds: 3),
+    );
+    await history.save(
+      'profile-a',
+      'drama-a',
+      'episode-2',
+      const Duration(seconds: 5),
+    );
+    expect(
+      await history.positionFor('profile-a', 'drama-a', 'episode-1'),
+      const Duration(seconds: 3),
+    );
+    expect(
+      await history.positionFor('profile-b', 'drama-a', 'episode-1'),
+      isNull,
+    );
+    expect(await history.lastEpisodeId('profile-a', 'drama-a'), 'episode-2');
+    expect(await history.lastEpisodeId('profile-a', 'drama-b'), isNull);
+  });
+}