{"message":"口算挑战排行榜 API","endpoints":{"GET /api/leaderboard":"获取排行榜（?mode=1digit|2digit|mixed）","GET /api/location":"获取地理位置","POST /api/submit":"提交分数（body: {name, score, location?, mode?})","GET /api/random-names":"获取随机用户名（?count=6）","POST /api/admin/update-names":"更新随机用户名列表"}}