fix(player): 修复详情往返播放位置丢失

test/player/player_logic_test.dart

@@ -5,6 +5,7 @@ import 'package:video_player/video_player.dart';
 import 'package:fruitshorts/core/data/models/drama.dart';
 import 'package:fruitshorts/core/data/models/play_ticket.dart';
 import 'package:fruitshorts/core/data/models/player_port.dart';
+import 'package:fruitshorts/core/data/models/watch_progress.dart';
 import 'package:fruitshorts/core/data/models/download_license.dart';
 import 'package:fruitshorts/core/data/models/download_policy.dart';
 import 'package:fruitshorts/core/data/repositories/download_repository.dart';
@@ -12,6 +13,7 @@ import 'package:fruitshorts/core/data/services/android_picture_in_picture.dart';
 import 'package:fruitshorts/core/data/services/download_controller.dart';
 import 'package:fruitshorts/core/data/services/download_storage.dart';
 import 'package:fruitshorts/core/data/services/playback_session.dart';
+import 'package:fruitshorts/core/data/services/playback_position_cache.dart';
 import 'package:fruitshorts/core/data/services/video_player_port.dart';
 import 'package:fruitshorts/pages/player/player_logic.dart';
 import 'package:fruitshorts/pages/player/player_view.dart';
@@ -48,11 +50,13 @@ AndroidPictureInPicture _pip() =>
 PlayerLogic _logic(
   FakeWatchHistory history, {
   PlaybackRepository? playback,
+  PlaybackPositionCache? positionCache,
   Future<void> Function()? waitForFrame,
 }) => PlayerLogic(
   history: history,
   playback: playback ?? FakePlaybackRepository(),
   pictureInPicture: _pip(),
+  positionCache: positionCache,
   waitForFrame: waitForFrame ?? () async {},
 );
 
@@ -126,6 +130,96 @@ void main() {
     });
   });
 
+  group('playback position cache', () {
+    test('should_use_cached_resume_point_without_reading_history', () async {
+      final history = FakeWatchHistory()..saved = const Duration(seconds: 12);
+      final cache = PlaybackPositionCache();
+      cache.save(
+        episodeId: 'signal-1',
+        dramaId: 'signal',
+        position: const Duration(minutes: 1, seconds: 20),
+        duration: const Duration(minutes: 3),
+      );
+      final logic = _logic(history, positionCache: cache);
+      logic.attach(
+        PlayerPage(drama: _drama('signal'), initialIndex: 0, active: false),
+        isMounted: () => true,
+      );
+      logic.start(
+        factory: _RecordingFactory().create,
+        coordinator: PlaybackCoordinator(),
+      );
+      await _drain(logic);
+      await pumpEventQueue();
+
+      expect(logic.resumePoint?.position, const Duration(seconds: 80));
+      expect(history.reads, isEmpty);
+      logic.dispose();
+      await _drain(logic);
+    });
+
+    test('should_fall_back_to_server_when_cache_belongs_to_other_drama',
+        () async {
+      final history = FakeWatchHistory()
+        ..records['signal'] = const WatchProgress(
+          dramaId: 'signal',
+          episodeId: 'signal-2',
+          position: Duration(seconds: 42),
+          duration: Duration(minutes: 3),
+        );
+      final cache = PlaybackPositionCache();
+      cache.save(
+        episodeId: 'signal-1',
+        dramaId: 'other-drama',
+        position: const Duration(seconds: 80),
+        duration: const Duration(minutes: 3),
+      );
+      final logic = _logic(history, positionCache: cache);
+      logic.attach(
+        PlayerPage(drama: _drama('signal'), initialIndex: 0, active: false),
+        isMounted: () => true,
+      );
+      logic.start(
+        factory: _RecordingFactory().create,
+        coordinator: PlaybackCoordinator(),
+      );
+      await _drain(logic);
+      await pumpEventQueue();
+
+      expect(logic.resumePoint?.episodeId, 'signal-2');
+      expect(logic.resumePoint?.position, const Duration(seconds: 42));
+      expect(history.reads, ['signal']);
+      logic.dispose();
+      await _drain(logic);
+    });
+
+    test('should_fall_back_to_server_when_cache_is_missing', () async {
+      final history = FakeWatchHistory()
+        ..records['signal'] = const WatchProgress(
+          dramaId: 'signal',
+          episodeId: 'signal-1',
+          position: Duration(seconds: 36),
+          duration: Duration(minutes: 3),
+        );
+      final logic = _logic(history);
+      logic.attach(
+        PlayerPage(drama: _drama('signal'), initialIndex: 0, active: false),
+        isMounted: () => true,
+      );
+      logic.start(
+        factory: _RecordingFactory().create,
+        coordinator: PlaybackCoordinator(),
+      );
+      await _drain(logic);
+      await pumpEventQueue();
+
+      expect(logic.resumePoint?.position, const Duration(seconds: 36));
+      expect(history.reads, ['signal']);
+      logic.dispose();
+      await _drain(logic);
+    });
+  });
+
   test('should_play_local_file_without_ticket_when_episode_is_downloaded',
       () async {
     final playback = FakePlaybackRepository();