feat(player): 保持屏幕常亮并自动恢复播放

lib/core/data/services/playback_session.dart

@@ -92,6 +92,7 @@ class PlaybackSession extends ChangeNotifier {
     }
     return slot.player;
   }
+
   bool get loading => _loading;
   bool get userWantsPlay => _userWantsPlay;
   bool get canAutoAdvance => _mayPlay && !_loading && active != null;
@@ -103,6 +104,10 @@ class PlaybackSession extends ChangeNotifier {
   Future<void> get playbackSettled => _operations;
   Future<void> get preloadSettled => _preloadTask;
 
+  /// 当前页面可见、无浮层遮挡且存在可用播放器时可安全恢复。
+  bool get canResumeAfterBackground =>
+      !_closed && _routeVisible && !_overlayOpen && active != null;
+
   bool get _visible => !_closed && _appResumed && _routeVisible;
   bool get _mayPlay => _visible && !_overlayOpen && _userWantsPlay;
 

lib/pages/player/player_logic.dart

@@ -512,6 +512,7 @@ class PlayerLogic extends ChangeNotifier {
   void onLifecycle(AppLifecycleState state) {
     if (state != AppLifecycleState.resumed) unawaited(saveCurrentProgress());
     if (state == AppLifecycleState.resumed) {
+      final wasInPip = pip || pipPreparing;
       // 部分机型退出画中画不会回调 onPipChanged(false)：回前台先兜底复位，
       // 否则 chromeHidden 恒为 true，播放浮层与首页底栏都会消失。
       if (pip || pipPreparing) {
@@ -523,8 +524,17 @@ class PlayerLogic extends ChangeNotifier {
       // 签名地址有有效期：回前台时若票据已过期，重新取一张再起播，
       // 否则会撞上 403（契约 §1.4）
       final episode = trackedEpisode;
+      final shouldAutoResume = !wasInPip && _canAutoResume(episode);
       if (episode != null && !playback.isFresh(episode.id)) {
-        unawaited(selectEpisode(session.currentIndex));
+        unawaited(
+          _refreshTicketThenResume(
+            episode,
+            session.currentIndex,
+            shouldAutoResume,
+          ),
+        );
+      } else if (shouldAutoResume) {
+        session.setUserWantsPlay(true);
       }
     }
     session.setAppResumed(
@@ -533,6 +543,31 @@ class PlayerLogic extends ChangeNotifier {
     if (state != AppLifecycleState.resumed) cancelScrub();
   }
 
+  Future<void> _refreshTicketThenResume(
+    Episode episode,
+    int index,
+    bool shouldResume,
+  ) async {
+    await selectEpisode(index);
+    if (!shouldResume ||
+        !isMounted() ||
+        trackedEpisode?.id != episode.id ||
+        !_canAutoResume(episode)) {
+      return;
+    }
+    session.setUserWantsPlay(true);
+  }
+
+  bool _canAutoResume(Episode? episode) {
+    return episode != null &&
+        ticketError == null &&
+        blockedEpisodeId != episode.id &&
+        unlockingEpisodeId == null &&
+        !session.isLocked &&
+        session.error == null &&
+        session.canResumeAfterBackground;
+  }
+
   @override
   void dispose() {
     if (_disposed) return;