Prepared ledger actions awaiting this party's signature

Every action waiting on this party's signature: the ones calls returned (a quote, an accept, a deposit accept, a withdrawal), plus any the desk queued itself for a trade you accepted (an allocation the accept could not queue at once, or a fresh one replacing an action that expired or was lost to a desk restart). Sign what is listed here after a lost response, and keep draining it while a trade of yours settles. Each action is a `SignActionDto` with a `hash` (base64 bytes of a Canton prepared-transaction hash): sign the RAW bytes (not the base64 text) with the party's Ed25519 key and call `POST /tx/execute`. An action leaves this list when it executes, when it expires (10 minutes), or when its flow dies first (a quote's actions go with the quote at its `validUntil`). Always empty for parties the desk signs for.

curl -X GET "https://example.com/tx/pending"

{  "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"}