提交提现

Rocky 实现： POST /v1/withdrawals ✓

从 user_id 钱包提出 amount 单位 asset 到 Canton party dest_user_handle_party。

请求

POST /v1/withdrawals
Content-Type: application/json

{
  "user_id": "5cfb031b-5936-4467-9533-cd2df576dbb8",
  "asset": "CC",
  "amount": "10.0",
  "dest_user_handle_party": "alice::1220abc...",
  "idempotency_key": "ui-withdraw-1748275200"
}

响应 — 200

{ "withdrawal_id": "8c9a1f2e7b6d5c4a3b2c1d0e9f8a7b6c" }

错误：400 UUID / amount / party 非法、409 幂等撞车、422 余额不足、503 trading service 挂掉。