[POST]
summary = "手机验证码登录：下发验证码"
docstring = "生成 6 位验证码存共享缓存（300s）。演示模式随响应返回 dev_code，生产接短信通道后返回 dev_code=null。"
auth_required = false
cacheable = false
params = ["phone: str"]

[POST.response_model]
result = { type = "str", required = true }
message = { type = "str", required = true }
expires_in = { type = "int", required = false, default = 300 }
dev_code = { type = "str", required = false }