refactor(PostCard, PostCard.legacy): remove legacy PostCard component and update exports

- Deleted the legacy PostCard component to streamline the codebase and improve maintainability.
- Updated exports in PostCard and index files to remove references to the legacy component.
- Adjusted PostCardProps to eliminate legacy properties, ensuring only the new API is supported.
- Enhanced the PostCard component to focus on modern implementation and features.

src/data/repositories/PostRepository.ts

@@ -47,6 +47,8 @@ interface PostApiResponse {
     username: string;
     nickname?: string;
     avatar?: string;
+    is_following?: boolean;
+    is_following_me?: boolean;
   };
 }
 
@@ -102,6 +104,9 @@ export class PostRepository implements IPostRepository {
         username: model.author.username,
         nickname: model.author.nickname,
         avatar: model.author.avatar,
+        // 关注关系直接透传 API 字段，供详情页关注按钮状态使用
+        is_following: response.author?.is_following,
+        is_following_me: response.author?.is_following_me,
       } : undefined,
       title: model.title,
       content: model.content,
@@ -286,20 +291,7 @@ export class PostRepository implements IPostRepository {
    */
   async getPostById(id: string): Promise<Post | null> {
     try {
-      // 1. 先查内存缓存
-      const memoryCached = this.getFromMemoryCache(id);
-      if (memoryCached) {
-        return memoryCached;
-      }
-
-      // 2. 查本地数据库缓存
-      const localCached = await this.getFromLocalCache(id);
-      if (localCached) {
-        this.saveToMemoryCache(localCached);
-        return localCached;
-      }
-
-      // 3. 从API获取
+      // 详情页优先取最新服务端数据，避免旧缓存导致关注态等关系字段过期
       const response = await this.api.get<PostApiResponse>(`/posts/${id}`);
       const post = this.mapToPost(response);
 
@@ -309,10 +301,16 @@ export class PostRepository implements IPostRepository {
 
       return post;
     } catch (error) {
-      // 如果API请求失败，尝试返回本地缓存
+      // API失败时再回退缓存，保证离线/弱网可用
+      const memoryCached = this.getFromMemoryCache(id);
+      if (memoryCached) {
+        console.warn('[PostRepository] API获取失败，使用内存缓存:', error);
+        return memoryCached;
+      }
       const localCached = await this.getFromLocalCache(id);
       if (localCached) {
         console.warn('[PostRepository] API获取失败，使用本地缓存:', error);
+        this.saveToMemoryCache(localCached);
         return localCached;
       }
       this.handleError(error, '获取帖子详情');