feat(player): 选集面板挑集后记住上次选集

lib/pages/player/player_logic.dart

@@ -173,6 +173,8 @@ class PlayerLogic extends ChangeNotifier {
   /// 推荐页每页一个 logic，若只保留最后一次注册的 handler，
   /// 相邻预加载页会盖掉正在播放页的注册，导致小窗 UI 不隐藏且无声音。
   static final Set<PlayerLogic> _pipSubscribers = <PlayerLogic>{};
+  /// 「记住上次选集」：dramaId → 集号。只在用户从选集面板主动挑集时写入
+  /// （见 [_recordPickedEpisode]），feed 里同一部剧据此显示上次选中的集。
   static final Map<String, int> pickedEpisode = {};
   final Set<String> _unlockedEpisodeIds = {};
   final Map<String, EpisodeStats> _episodeStats = {};
@@ -1608,6 +1610,7 @@ class PlayerLogic extends ChangeNotifier {
         _pendingSelectionIndex = null;
         _pendingSelectionRevision = null;
         await selectEpisode(index, revision: revision);
+        _recordPickedEpisode(index);
       }
     } finally {
       _selectionDrain = null;
@@ -1620,6 +1623,18 @@ class PlayerLogic extends ChangeNotifier {
     }
   }
 
+  /// 记录用户从选集面板主动挑的集，供 feed 侧「记住上次选集」展示。
+  /// 只在切集确实落到该集时记录，避免快速连点时把没播过的集记成"上次选集"。
+  void _recordPickedEpisode(int index) {
+    if (!_started || _disposed || session.currentIndex != index) return;
+    if (index < 0 || index >= sessionEpisodes.length) return;
+    final episode = sessionEpisodes[index];
+    final dramaId = _dramaIdForEpisode(episode.id);
+    if (dramaId != null) {
+      pickedEpisode[dramaId] = episode.number;
+    }
+  }
+
   Future<void> selectEpisode(
     int index, {
     int? revision,