fix(database): 修复用户表关联查询的数据库模式问题

- 修改 AppUserMapper.xml 中的 LEFT JOIN 语句
- 为 sys_user 表添加 gxwebsoft_core 数据库前缀
- 确保跨数据库关联查询的正确性
- 保持与系统用户表的数据一致性

src/main/java/com/gxwebsoft/app/mapper/xml/AppUserMapper.xml

@@ -8,7 +8,7 @@
                u.nickname, u.avatar AS user_avatar, u.phone
         FROM app_user a
         LEFT JOIN cms_website w ON a.website_id = w.website_id AND w.deleted = 0
-        LEFT JOIN sys_user u ON a.user_id = u.user_id
+        LEFT JOIN gxwebsoft_core.sys_user u ON a.user_id = u.user_id
         <where>
             <if test="param.id != null">
                 AND a.id = #{param.id}