feat(recommend): 新增推荐频道页并恢复首页沉浸式信息流

- tab1 推荐页改为接口分类频道：频道导航可横滑，选中频道自动滚动到可视区，内容区左右滑动切换分类
- 精选频道：顶部固定高度 banner 轮播图 + 接口 tag 筛选的上新短剧横滑 + 其余短剧双列网格；其他分类三列网格
- 分类内容支持懒加载、下拉刷新与上拉分页加载
- 卡片角标文案与背景色取自接口 tag/tagColor，短剧标题统一白色
- 恢复 tab0 为沉浸式全屏视频首页及其三 inner-tab 顶导（搜索/礼物入口）
- l10n 新增原创出品、立即观看、上新、编辑精选、全N集等多语言文案

lib/pages/player/widgets/interaction_rail.dart

@@ -5,8 +5,10 @@ import 'package:flutter/material.dart';
 import '../../../core/formatting/count_format.dart';
 import '../../../core/theme/app_colors.dart';
 
-const double _buttonSize = 44;
-const double _iconSize = 32;
+const double _defaultButtonSize = 44;
+const double _defaultIconSize = 32;
+const double _defaultCountFont = 12;
+const double _defaultIconCountGap = 2;
 const double _defaultItemGap = 24;
 
 /// 互动栏单项：图标、计数与点击。
@@ -21,6 +23,7 @@ class InteractionRailItem {
     this.countKey,
     this.selected = false,
     this.selectedColor = AppColors.blue,
+    this.mirrorIcon = false,
   }) : assert((asset == null) != (icon == null));
 
   final Key key;
@@ -32,6 +35,9 @@ class InteractionRailItem {
   final Key? countKey;
   final bool selected;
   final Color selectedColor;
+
+  /// 水平镜像图标（分享弯箭头用 reply 镜像得到）。
+  final bool mirrorIcon;
 }
 
 /// 播放页与首页 feed 共用的右侧互动栏：收藏/评论/喜欢/分享。
@@ -40,10 +46,18 @@ class InteractionRail extends StatelessWidget {
     super.key,
     required this.items,
     this.itemGap = _defaultItemGap,
+    this.buttonSize = _defaultButtonSize,
+    this.iconSize = _defaultIconSize,
+    this.countFontSize = _defaultCountFont,
+    this.iconCountGap = _defaultIconCountGap,
   });
 
   final List<InteractionRailItem> items;
   final double itemGap;
+  final double buttonSize;
+  final double iconSize;
+  final double countFontSize;
+  final double iconCountGap;
 
   @override
   Widget build(BuildContext context) {
@@ -52,7 +66,13 @@ class InteractionRail extends StatelessWidget {
       children: [
         for (var index = 0; index < items.length; index++) ...[
           if (index > 0) SizedBox(height: itemGap),
-          _RailButton(item: items[index]),
+          _RailButton(
+            item: items[index],
+            buttonSize: buttonSize,
+            iconSize: iconSize,
+            countFontSize: countFontSize,
+            iconCountGap: iconCountGap,
+          ),
         ],
       ],
     );
@@ -60,53 +80,61 @@ class InteractionRail extends StatelessWidget {
 }
 
 class _RailButton extends StatelessWidget {
-  const _RailButton({required this.item});
+  const _RailButton({
+    required this.item,
+    required this.buttonSize,
+    required this.iconSize,
+    required this.countFontSize,
+    required this.iconCountGap,
+  });
 
   final InteractionRailItem item;
+  final double buttonSize;
+  final double iconSize;
+  final double countFontSize;
+  final double iconCountGap;
 
   @override
   Widget build(BuildContext context) {
+    final tint = item.selected ? item.selectedColor : AppColors.onPrimary;
     return Column(
       key: item.key,
       mainAxisSize: MainAxisSize.min,
       children: [
         SizedBox.square(
-          dimension: _buttonSize,
+          dimension: buttonSize,
           child: IconButton(
             onPressed: item.onTap,
             padding: EdgeInsets.zero,
             icon: item.asset != null
                 ? Image.asset(
                     item.asset!,
-                    width: _iconSize,
-                    height: _iconSize,
+                    width: iconSize,
+                    height: iconSize,
                     fit: BoxFit.contain,
-                    color: item.selected
-                        ? item.selectedColor
-                        : AppColors.onPrimary,
+                    color: tint,
                     colorBlendMode: BlendMode.srcIn,
                   )
-                : Icon(
-                    item.icon,
-                    size: _iconSize,
-                    color: item.selected
-                        ? item.selectedColor
-                        : AppColors.onPrimary,
+                : Transform.flip(
+                    flipX: item.mirrorIcon,
+                    child: Icon(item.icon, size: iconSize, color: tint),
                   ),
           ),
         ),
-        const SizedBox(height: 2),
+        SizedBox(height: iconCountGap),
         Text(
           item.count == null ? item.label : formatInteractionCount(item.count!),
           key: item.countKey,
           maxLines: 1,
           overflow: TextOverflow.ellipsis,
-          style: const TextStyle(
+          style: TextStyle(
             color: AppColors.onPrimary,
             height: 1,
-            fontSize: 12,
+            fontSize: countFontSize,
             fontWeight: FontWeight.w600,
-            shadows: [Shadow(blurRadius: 6, color: AppColors.mediaBlack)],
+            shadows: const [
+              Shadow(blurRadius: 6, color: AppColors.mediaBlack),
+            ],
           ),
         ),
       ],