fix(home): 修复分类分页控制器初始化

lib/pages/home/widgets/home_feed_grid.dart

@@ -43,8 +43,10 @@ class HomeFeedGrid extends StatefulWidget {
 
 class _HomeFeedGridState extends State<HomeFeedGrid> {
   HomePrimaryTab _selectedPrimary = HomePrimaryTab.featured;
-  late final PageController _pageController;
-  late final Map<HomePrimaryTab, ScrollController> _scrollControllers;
+  final PageController _pageController = PageController();
+  final Map<HomePrimaryTab, ScrollController> _scrollControllers = {
+    for (final tab in HomePrimaryTab.values) tab: ScrollController(),
+  };
   final Map<HomePrimaryTab, String?> _selectedTags = {
     for (final tab in HomePrimaryTab.values) tab: null,
   };
@@ -52,10 +54,11 @@ class _HomeFeedGridState extends State<HomeFeedGrid> {
   @override
   void initState() {
     super.initState();
-    _pageController = PageController(initialPage: _selectedPrimary.index);
-    _scrollControllers = {
-      for (final tab in HomePrimaryTab.values) tab: ScrollController(),
-    };
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (mounted && _pageController.hasClients) {
+        _pageController.jumpToPage(_selectedPrimary.index);
+      }
+    });
   }
 
   @override