refactor(ui): 清理 K26 旧 UI 与死代码

test/player/player_fullscreen_test.dart

@@ -81,9 +81,6 @@ void _expectFullscreenOverlay() {
 
   expect(find.byKey(const Key('rail-like')), findsNothing);
   expect(find.byKey(const Key('rail-save')), findsNothing);
-  expect(find.byKey(const Key('card-player-video-frame')), findsNothing);
-  expect(find.byKey(const Key('card-player-progress')), findsNothing);
-  expect(find.byKey(const Key('card-player-next')), findsNothing);
 }
 
 Future<void> _pumpApp(WidgetTester tester) async {

test/player/player_logic_test.dart

@@ -117,33 +117,7 @@ void main() {
   });
 
   group('surface flags', () {
-    test('should_hide_chrome_until_restored_when_screen_is_cleared', () {
-      final logic = _logic(FakeWatchHistory());
-      final immersive = <bool>[];
-      logic.onImmersiveChanged = immersive.add;
-      var notifications = 0;
-      logic.addListener(() => notifications++);
-
-      expect(logic.chromeHidden, isFalse);
-      expect(logic.immersive, isFalse);
-
-      logic.setScreenCleared(true);
-      expect(logic.chromeHidden, isTrue);
-      expect(notifications, 1);
-      expect(immersive, [true]);
-
-      // Repeating the same value is not a state change.
-      logic.setScreenCleared(true);
-      expect(notifications, 1);
-      expect(immersive, [true]);
-
-      logic.setScreenCleared(false);
-      expect(logic.chromeHidden, isFalse);
-      expect(notifications, 2);
-      expect(immersive, [true, false]);
-    });
-
-    test('should_outrank_cleared_screen_flag_when_picture_in_picture_callback_fires', () async {
+    test('should_set_immersive_when_picture_in_picture_callback_fires', () async {
       final factory = _RecordingFactory();
       final drama = _drama('signal');
       final logic = _logic(FakeWatchHistory());