feat(pagination): add updateItem for in-place list updates and optimize notifications

Add `updateItem` function to cursor pagination hook for updating single items
without full list refresh. Use this in NotificationsScreen to mark messages
as read locally instead of refetching. Also add `is_blocked` detection in
postService and userProfile to show blocked state in profile screen.

src/infrastructure/pagination/types.ts

@@ -240,6 +240,8 @@ export interface CursorPaginationActions<T> {
   reset: () => void;
   /** 设置数据（用于外部数据注入） */
   setList: (list: T[], nextCursor: string | null, prevCursor: string | null, hasMore: boolean) => void;
+  /** 就地更新单条数据 */
+  updateItem: (id: string, updates: Partial<T>) => void;
 }
 
 /**