Refactor authentication logic to unify user account handling and update database schema for user accounts

src/main/resources/mapper/admin/AdminUserMapper.xml

@@ -1,21 +0,0 @@
-<?xml version="1.0" encoding="UTF-8" ?>
-<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
-<mapper namespace="com.gameplatform.server.mapper.admin.AdminUserMapper">
-    <resultMap id="AdminUserMap" type="com.gameplatform.server.model.entity.admin.AdminUser">
-        <id property="id" column="id" />
-        <result property="username" column="username" />
-        <result property="passwordHash" column="password_hash" />
-        <result property="role" column="role" />
-        <result property="status" column="status" />
-        <result property="createdAt" column="created_at" />
-        <result property="updatedAt" column="updated_at" />
-    </resultMap>
-
-    <select id="findByUsername" parameterType="string" resultMap="AdminUserMap">
-        SELECT id, username, password_hash, role, status, created_at, updated_at
-        FROM admin_user
-        WHERE username = #{username}
-        LIMIT 1
-    </select>
-</mapper>
-