fix(home): 调整榜单版式并去掉二级分类

lib/pages/home/widgets/home_feed_grid.dart

@@ -14,6 +14,7 @@ import '../../../core/data/services/home_feed_controller.dart';
 import '../../../core/data/services/wallet_controller.dart';
 import '../../../core/theme/app_colors.dart';
 import '../../../core/theme/app_dimens.dart';
+import '../../../core/theme/app_theme.dart';
 import '../../../core/widgets/app_pull_to_refresh.dart';
 import '../../../core/widgets/drama_grid_skeleton.dart';
 import '../../../core/widgets/empty_state.dart';
@@ -81,17 +82,16 @@ class _HomeFeedGridState extends State<HomeFeedGrid> {
     final auth = context.watch<AuthController>();
     final wallet = context.watch<WalletController>();
     final shortcuts = _categoryShortcuts(categories, l10n);
-    final tags = _availableTags(l10n);
-    final activeTag =
-        tags.any((tag) => tag.id == _selectedTags[_selectedPrimary])
-        ? _selectedTags[_selectedPrimary]
-        : null;
     final walletBadge = auth.isSignedIn && wallet.snapshot != null
         ? wallet.balance
         : null;
-    return ColoredBox(
+    final ranking = _selectedPrimary == HomePrimaryTab.ranking;
+    return DecoratedBox(
       key: const Key('home-grid'),
-      color: AppColors.appBackground,
+      decoration: BoxDecoration(
+        color: ranking ? null : AppColors.appBackground,
+        gradient: ranking ? AppTheme.pageGradient : null,
+      ),
       child: SafeArea(
         bottom: false,
         child: Column(
@@ -100,12 +100,8 @@ class _HomeFeedGridState extends State<HomeFeedGrid> {
             HomeGridHeader(
               callbacks: widget.callbacks,
               categories: shortcuts,
-              tags: tags,
               selectedPrimary: _selectedPrimary,
-              selectedTag: activeTag,
               onPrimarySelected: _selectPrimary,
-              onTagSelected: (tag) =>
-                  setState(() => _selectedTags[_selectedPrimary] = tag),
               walletBadge: walletBadge,
             ),
             Expanded(
@@ -322,17 +318,6 @@ class _HomeFeedGridState extends State<HomeFeedGrid> {
     return null;
   }
 
-  List<HomeGridTagOption> _availableTags(AppLocalizations l10n) {
-    // UI 先完整展示筛选维度；后续接口补齐题材字段时只替换数据来源。
-    return [
-      HomeGridTagOption(id: 'hot', label: l10n.homeTagHot),
-      HomeGridTagOption(id: 'uplifting', label: l10n.homeTagUplifting),
-      HomeGridTagOption(id: 'sweet', label: l10n.homeTagSweet),
-      HomeGridTagOption(id: 'faceSlap', label: l10n.homeTagFaceSlap),
-      HomeGridTagOption(id: 'angst', label: l10n.homeTagAngst),
-    ];
-  }
-
   List<Drama> _dramasFor(
     HomePrimaryTab tab,
     String? tag,