fix(player): 解锁状态登录期内共享，重进播放页不再丢解锁

解锁记录原本是播放页实例的私有集合，退出再进入会先闪一次锁定态，还会
被 selectLocked 提前释放播放器。改为进程内共享的 UnlockedEpisodeRegistry，
由全局注入并在登录态变化时清空；播放器三处渲染分支统一走同一判定，
会话锁态只约束当前页，避免相邻预加载页被误判为锁定。

lib/pages/player/player_logic.dart

@@ -27,6 +27,7 @@ import '../../core/data/services/platform_share_service.dart';
 import '../../core/data/services/playback_position_cache.dart';
 import '../../core/data/services/playback_queue.dart';
 import '../../core/data/services/playback_session.dart';
+import '../../core/data/services/unlocked_episode_registry.dart';
 import '../../core/data/services/video_player_port.dart';
 import '../../core/data/services/wallet_controller.dart';
 import '../../core/formatting/localized_content.dart';
@@ -64,11 +65,13 @@ class PlayerLogic extends ChangeNotifier {
     required this.pictureInPicture,
     this.wallet,
     this.downloads,
+    UnlockedEpisodeRegistry? unlockedEpisodes,
     PlaybackPositionCache? positionCache,
     Future<void> Function()? waitForFrame,
     DateTime Function()? clock,
     bool Function()? isSignedIn,
-  }) : positionCache = positionCache ?? PlaybackPositionCache(),
+  }) : unlockedEpisodes = unlockedEpisodes ?? UnlockedEpisodeRegistry(),
+       positionCache = positionCache ?? PlaybackPositionCache(),
        _waitForFrame =
            waitForFrame ?? (() => WidgetsBinding.instance.endOfFrame),
        _clock = clock ?? DateTime.now,
@@ -79,6 +82,9 @@ class PlayerLogic extends ChangeNotifier {
   final AndroidPictureInPicture pictureInPicture;
   final WalletController? wallet;
   final DownloadController? downloads;
+
+  /// 已确认可播的收费集（登录期内共享）：退出播放页再进来不必重新挡一次。
+  final UnlockedEpisodeRegistry unlockedEpisodes;
   final PlaybackPositionCache positionCache;
   final Future<void> Function() _waitForFrame;
   final DateTime Function() _clock;
@@ -169,14 +175,15 @@ class PlayerLogic extends ChangeNotifier {
 
   /// 当前设备是否为 iOS 真机环境（面板据此显示自动小窗开关）。
   bool get iosDevice => !kIsWeb && Platform.isIOS;
+
   /// PiP 状态是全局单通道回调，须广播给所有存活的 PlayerLogic：
   /// 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 = {};
   final Map<String, DateTime> _episodeStatsFetchedAt = {};
   final Map<String, Future<void>> _episodeStatsInFlight = {};
@@ -562,7 +569,7 @@ class PlayerLogic extends ChangeNotifier {
       final localPath = await downloads?.findLocalPath(episode.id);
       if (request != pageRequest) return false;
       if (localPath != null) {
-        _unlockedEpisodeIds.add(episode.id);
+        unlockedEpisodes.markUnlocked(episode.id);
         blockedTicket = null;
         blockedEpisodeId = null;
         qualities = const [];
@@ -587,7 +594,7 @@ class PlayerLogic extends ChangeNotifier {
       final playUrl = preferred ?? ticket.playUrl;
       if (preferred == null) selectedQuality = 'AUTO';
       if (ticket.accessible && playUrl.isNotEmpty) {
-        _unlockedEpisodeIds.add(episode.id);
+        unlockedEpisodes.markUnlocked(episode.id);
         // 签名地址原样写回，不做任何拼接/改写（AppConfig.mediaUrl 只补 host）
         sessionEpisodes[index] = episode.withVideoUrl(
           playUrl,
@@ -860,7 +867,7 @@ class PlayerLogic extends ChangeNotifier {
         unlockError = service.unlockError;
         return false;
       }
-      _unlockedEpisodeIds.add(episode.id);
+      unlockedEpisodes.markUnlocked(episode.id);
       final ready = await ensureTicket(index, forceRefresh: true);
       if (ready) {
         await _selectVisible(index);
@@ -1688,7 +1695,16 @@ class PlayerLogic extends ChangeNotifier {
   /// 收费集只有在本会话确认可播或解锁成功后才解除门禁。
   bool isEpisodeLocked(Episode episode) {
     return (episode.locked || !episode.isFree) &&
-        !_unlockedEpisodeIds.contains(episode.id);
+        !unlockedEpisodes.contains(episode.id);
+  }
+
+  /// 单页锁定判定：剧集自身锁定 + 会话锁态（只约束当前页）+ 后端拒绝。
+  ///
+  /// 播放页的多个渲染分支都必须走这里，否则相邻预加载页会被会话锁态误判成锁定。
+  bool isEpisodeBlockedFor(Episode episode, int index) {
+    return isEpisodeLocked(episode) ||
+        (index == session.currentIndex && session.isLocked) ||
+        blockedEpisodeId == episode.id;
   }
 
   /// 按可见队列选择一集，并预热上一集与下一集。