管理员：列出排行榜用户

{
    "code": 200,
    "status": "success",
    "total": 2,
    "users": [
        {
            "user_id": "TVVMKK3G",
            "username": "小明",
            "ip_location": "内网/保留地址",
            "create_time": "2026-07-20T16:14:10",
            "update_time": "2026-07-20T16:14:10",
            "easy_total": 2,
            "medium_total": 1,
            "hard_total": 0
        },
        {
            "user_id": "FR9V765N",
            "username": "小明",
            "ip_location": "内网/保留地址",
            "create_time": "2026-07-20T16:13:41",
            "update_time": "2026-07-20T16:13:41",
            "easy_total": 0,
            "medium_total": 0,
            "hard_total": 0
        }
    ]
}