feat(following): 新增追剧三栏与双列网格

test/home/k28_a_navigation_test.dart

@@ -36,8 +36,7 @@ void main() {
     await tester.tap(find.byKey(const Key('tab-follow')));
     await tester.pumpAndSettle();
 
-    expect(find.byKey(const Key('favorites-page')), findsOneWidget);
-    expect(find.byKey(const Key('favorites-back')), findsNothing);
+    expect(find.byKey(const Key('following-page')), findsOneWidget);
     expect(find.byType(AppBottomNav), findsOneWidget);
   });