GET /api/payments/providers — 已启用的支付渠道

curl https://ariacompute.cn/api/payments/providers

{
  "providers": [
    { "name": "wechat", "enabled": true, "currency": "CNY", "region": "cn" },
    { "name": "alipay", "enabled": true, "currency": "CNY", "region": "cn" }
  ]
}