fix(player): iOS自动小窗仅在播放页活跃时拉起

lib/pages/player/player_logic.dart

@@ -133,6 +133,29 @@ class PlayerLogic extends ChangeNotifier {
   static const _iosAutoPipPrefKey = 'player.ios.autoEnterPip';
   bool iosAutoPipEnabled = false;
 
+  /// 播放页前台活跃标志：沉浸流切走 tab / 独立页关闭后置 false，
+  /// 此时退后台不再自动拉起画中画（影子只同步不拉起）。
+  bool pipPageActive = false;
+
+  /// 由播放视图同步活跃标志；离开播放页时撤销影子的自动小窗资格，
+  /// 重新进入时重建影子待命（切走期间视图可能被卸载、逻辑实例已换新）。
+  void setPipPageActive(bool active) {
+    debugPrint('pip: page-active -> $active');
+    if (pipPageActive == active) return;
+    pipPageActive = active;
+    if (!active && iosDevice) {
+      unawaited(pictureInPicture.disarmAutoEnter());
+      return;
+    }
+    if (active && iosDevice && iosAutoPipEnabled && !pip) {
+      final episode = trackedEpisode;
+      if (episode != null) {
+        debugPrint('pip: page re-entered, ensure shadow standby');
+        unawaited(_ensureIosShadowStandby(episode));
+      }
+    }
+  }
+
   /// 画中画还原信号：自增通知视频表面回退占位重新等首帧（防回前台黑屏）。
   int pipResumeToken = 0;
 
@@ -925,7 +948,14 @@ class PlayerLogic extends ChangeNotifier {
       final video = session.active is VideoPlayerPort
           ? session.active as VideoPlayerPort
           : null;
+      if (state == AppLifecycleState.inactive) {
+        debugPrint(
+          'pip: inactive gate pageActive=$pipPageActive '
+          'video=${video != null} userWantsPlay=${session.userWantsPlay}',
+        );
+      }
       if (state == AppLifecycleState.inactive &&
+          pipPageActive &&
           video != null &&
           session.userWantsPlay) {
         debugPrint('pip: lifecycle inactive -> arm auto enter');