feat(player): 增加进度条拖动画面预览

lib/pages/player/widgets/player_overlay_models.dart

@@ -4,6 +4,7 @@ import 'package:flutter/widgets.dart';
 import 'package:video_player/video_player.dart';
 
 import '../../../core/data/models/drama.dart';
+import '../../../core/data/services/playback_thumbnail_service.dart';
 import '../../../l10n/app_localizations.dart';
 
 /// 播放浮层展示数据。
@@ -24,6 +25,7 @@ class PlayerOverlayData {
     required this.totalEpisodes,
     required this.boosting,
     required this.locked,
+    this.thumbnailService,
     this.authorNote = '',
   });
 
@@ -69,6 +71,9 @@ class PlayerOverlayData {
   /// 当前剧集是否锁定。
   final bool locked;
 
+  /// 拖动进度时按当前集和时间点取帧。
+  final PlaybackThumbnailService? thumbnailService;
+
   /// 作者声明；没有后端字段时为空。
   final String authorNote;
 }