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/screens/message/NotificationsScreen.tsx

@@ -110,6 +110,7 @@ export const NotificationsScreen: React.FC<{ onBack?: () => void }> = ({ onBack
     hasMore,
     loadMore,
     refresh,
+    updateItem,
     error: paginationError,
   } = useCursorPagination(fetchSystemMessages, { pageSize: 20 });
 
@@ -182,17 +183,16 @@ export const NotificationsScreen: React.FC<{ onBack?: () => void }> = ({ onBack
     }
   }, [refresh, setSystemUnreadCount]);
 
-  // 页面加载和获得焦点时刷新，并自动标记所有消息为已读
-  // 使用 ref 防止重复执行，避免无限循环
-  const hasInitializedRef = useRef(false);
+  // 页面获得焦点时刷新未读数并标记全部已读
+  const markAllReadAndRefreshRef = useRef(handleMarkAllRead);
+  markAllReadAndRefreshRef.current = handleMarkAllRead;
+
   useEffect(() => {
-    if (isFocused && !hasInitializedRef.current) {
-      hasInitializedRef.current = true;
+    if (isFocused) {
       fetchUnreadCount();
-      // 进入界面自动标记所有消息为已读
-      handleMarkAllRead();
+      markAllReadAndRefreshRef.current();
     }
-  }, [isFocused]); // 只依赖 isFocused，函数使用 ref 稳定引用
+  }, [isFocused]);
 
   // 启动入场动画
   useEffect(() => {
@@ -308,13 +308,11 @@ export const NotificationsScreen: React.FC<{ onBack?: () => void }> = ({ onBack
       const messageId = String(message.id);
       const wasUnread = message.is_read !== true;
       await messageService.markSystemMessageRead(messageId);
-      // 【游标分页】不再直接修改 messages 状态，而是通过刷新获取最新数据
       if (wasUnread) {
+        updateItem(messageId, { is_read: true });
         setUnreadCount(prev => Math.max(0, prev - 1));
         decrementSystemUnreadCount(1);
       }
-      // 更新本地未读数以及全局 TabBar 红点
-      fetchUnreadCount();
       messageManager.fetchUnreadCount();
 
       // 根据消息类型处理导航