feat(flutter): 重构播放页并增加语言切换

test/comment/drama_comments_sheet_test.dart

@@ -68,7 +68,7 @@ void main() {
     await tester.pumpAndSettle();
 
     expect(find.text('Second page'), findsOneWidget);
-    expect(find.text('Comments (2)'), findsOneWidget);
+    expect(find.text('2 comments'), findsOneWidget);
     expect(repository.pageCalls.last.cursor, '10');
   });