fix(flutter): 回前台复位残留画中画状态

lib/pages/player/player_logic.dart

@@ -313,6 +313,14 @@ class PlayerLogic extends ChangeNotifier {
   void onLifecycle(AppLifecycleState state) {
     if (state != AppLifecycleState.resumed) unawaited(saveCurrentProgress());
     if (state == AppLifecycleState.resumed) {
+      // 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) {
+        pip = false;
+        pipPreparing = false;
+        notify();
+        notifyImmersive();
+      }
       // 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;

test/player/player_logic_test.dart

@@ -187,6 +187,34 @@ void main() {
 
       expect(logic.pip, isFalse);
     });
+
+    test('should_clear_stale_pip_when_app_returns_to_foreground', () async {
+      final factory = _RecordingFactory();
+      final drama = _drama('signal');
+      final logic = _logic(FakeWatchHistory());
+      final immersive = <bool>[];
+      logic.attach(
+        PlayerPage(drama: drama, initialIndex: 0),
+        isMounted: () => true,
+      );
+      logic.onImmersiveChanged = immersive.add;
+      logic.start(factory: factory.create, coordinator: PlaybackCoordinator());
+      await _drain(logic);
+
+      // 模拟画中画已进入但退出时没有回调 false。
+      logic.onPipChanged(true);
+      expect(logic.chromeHidden, isTrue);
+
+      logic.onLifecycle(AppLifecycleState.resumed);
+
+      expect(logic.pip, isFalse);
+      expect(logic.pipPreparing, isFalse);
+      expect(logic.chromeHidden, isFalse);
+      expect(immersive.last, isFalse);
+
+      logic.dispose();
+      await _drain(logic);
+    });
   });
 
   group('history writes', () {