集成互动功能到帖子详情，删除独立互动页面

- 点赞/收藏改为纯 toggle，移除 unlike/unfavorite 参数
- 帖子详情 API 返回 isLiked/isFavorited 状态（SVG xlink:href 检测）
- 前端两个切换按钮替代原四个独立按钮
- 修复 __INITIAL_STATE__ Vue 响应式代理序列化（structuredClone + fallback）
- 修复 overlay 场景下点赞按钮误点 feed 列表元素（.last() 定位）
- 删除 InteractionsPage 及相关路由/导航

src/platforms/xiaohongshu/selectors.ts

@@ -190,15 +190,15 @@ export const XHS_SELECTORS = {
 
   interaction: {
     /** Like button on the feed detail page. */
-    likeButton: '.engage-bar .like-wrapper, span.like-wrapper',
+    likeButton: '.engage-bar-style .like-wrapper',
     /** Like button in active/liked state. */
-    likeButtonActive: '.engage-bar .like-wrapper.active, span.like-wrapper.active',
+    likeButtonActive: '.engage-bar-style .like-wrapper.like-active',
     /** Like count element next to the like button. */
     likeCount: '.engage-bar .like-wrapper .count',
     /** Favorite / collect button on the feed detail page. */
-    favoriteButton: '.engage-bar .collect-wrapper, span.collect-wrapper',
+    favoriteButton: '.engage-bar-style .collect-wrapper',
     /** Favorite button in active/favorited state. */
-    favoriteButtonActive: '.engage-bar .collect-wrapper.active, span.collect-wrapper.active',
+    favoriteButtonActive: '.engage-bar-style .collect-wrapper.collect-active',
     /** Favorite count element next to the favorite button. */
     favoriteCount: '.engage-bar .collect-wrapper .count',
     /** Container for the interaction bar at the bottom of a feed detail. */