优化：积分不够的时候跳转到充值页面

lib/features/home/home_screen.dart

@@ -294,6 +294,17 @@ class _HomeScreenState extends State<HomeScreen> {
   static const _placeholderImage =
       'https://images.unsplash.com/photo-1763929272543-0df093e4f659?w=400';
 
+  /// 与 [GenerateVideoScreen] 默认 480P 消耗一致；不足则去充值，够才进生图页
+  void _openGeneratePage(TaskItem task) {
+    final requiredCredits = task.credits480p ?? 50;
+    final balance = UserState.credits.value ?? 0;
+    if (balance < requiredCredits) {
+      Navigator.of(context).pushNamed('/recharge');
+      return;
+    }
+    Navigator.of(context).pushNamed('/generate', arguments: task);
+  }
+
   @override
   Widget build(BuildContext context) {
     return Scaffold(
@@ -376,10 +387,7 @@ class _HomeScreenState extends State<HomeScreen> {
                                   onStopRequested: () => setState(() =>
                                       _userPausedVideoIndices.add(index)),
                                   onGenerateSimilar: () =>
-                                      Navigator.of(context).pushNamed(
+                                      _openGeneratePage(task),
-                                    '/generate',
-                                    arguments: task,
-                                  ),
                                 ),
                               );
                             },