fix(player): 收紧图片与快速切集资源占用

lib/pages/player/player_logic.dart

@@ -93,6 +93,9 @@ class PlayerLogic extends ChangeNotifier {
   String selectedQuality = 'AUTO';
   Duration? _qualitySeek;
   int pageRequest = 0;
+  int? _pendingSelectionIndex;
+  int? _pendingSelectionRevision;
+  Future<void>? _selectionDrain;
   bool muted = false;
   double playbackSpeed = 1.0;
   bool stoppedAtFeedEnd = false;
@@ -957,6 +960,37 @@ class PlayerLogic extends ChangeNotifier {
     );
   }
 
+  /// 翻页入口使用 single-flight：执行中的切集不被重复排队，只保留最新目标。
+  Future<void> requestEpisodeSelection(int index, {int? revision}) {
+    if (_disposed || index < 0 || index >= sessionEpisodes.length) {
+      return Future<void>.value();
+    }
+    _pendingSelectionIndex = index;
+    _pendingSelectionRevision = revision;
+    return _selectionDrain ??= _drainEpisodeSelections();
+  }
+
+  Future<void> _drainEpisodeSelections() async {
+    try {
+      while (!_disposed) {
+        final index = _pendingSelectionIndex;
+        if (index == null) break;
+        final revision = _pendingSelectionRevision;
+        _pendingSelectionIndex = null;
+        _pendingSelectionRevision = null;
+        await selectEpisode(index, revision: revision);
+      }
+    } finally {
+      _selectionDrain = null;
+      final index = _pendingSelectionIndex;
+      if (!_disposed && index != null) {
+        unawaited(
+          requestEpisodeSelection(index, revision: _pendingSelectionRevision),
+        );
+      }
+    }
+  }
+
   Future<void> selectEpisode(int index, {int? revision}) async {
     final feedRevisionAtStart = revision ?? feedRevision;
     final request = ++pageRequest;