{"message":"Billing System API","version":"1.0.0","endpoints":{"credit":"POST /billing/credit - 充值","reserve":"POST /billing/reserve - 预扣","consume":"POST /billing/consume - 使用中扣费（增量模式）","settle":"POST /billing/settle - 结算","pricing":{"list":"GET /billing/pricing - 查询计价规则","create":"POST /billing/pricing - 创建计价规则"}}}