Accept a quote (taker) — atomic DvP settlement

Stages the trade — checks your funding and locks the quote — and answers **202** with `status: "settling"` plus `actions`: your own allocations to sign, one per instrument your legs touch (empty for a desk-signed house taker). Sign them all in one `POST /tx/execute`. One the desk could not queue at once follows as `sign.requested` (and in `GET /tx/pending`): until the outcome, sign what arrives for the trade. The desk adds its fee-receipt allocation and, once every allocation has landed, settles the trade in one transaction. The outcome arrives as `trade.settled` / `trade.failed` on the stream, or read it from `GET /trades` (settled) and `GET /rfq-history` (failed). A failed trade moves nothing; the quote is revoked and the RFQ stays open for another accept until its deadline. Unsigned allocations fail the trade about 11 minutes after the quote's `validUntil`; an action itself expires after 10, and until then the desk queues a fresh one in its place. An accept also drops any unsigned withdrawal of yours — or the maker's — in the trade's instruments, so it cannot spend the holdings the settlement needs: request it again after the outcome.

curl -X POST "https://example.com/quote/string/accept"

{  "tradeId": "string",  "taker": "string",  "maker": "string",  "direction": "SELL",  "qty": "string",  "base": "cbtc",  "quote": "usdcx",  "price": "string",  "fee": "string",  "settledAt": "string",  "status": "settled",  "ledger": {    "updateId": "string",    "receiptCids": [      "string"    ]  },  "actions": [    {      "id": "string",      "kind": "hash",      "purpose": "allocate",      "description": "Sign your quote 97300 (2/2: USDCx allocation)",      "hash": "string",      "tradeId": "string",      "createdAt": "2019-08-24T14:15:22Z",      "expiresAt": "2019-08-24T14:15:22Z"    }  ]}

{  "error": "string",  "code": "INSUFFICIENT_FUNDS"}

{  "error": "string",  "code": "INSUFFICIENT_FUNDS"}

{  "error": "string",  "code": "INSUFFICIENT_FUNDS"}

{  "error": "string",  "code": "INSUFFICIENT_FUNDS"}