Prepared ledger actions awaiting this party's signature

For node-hosted bot makers (and takers) whose party key is NOT held by the desk: every ledger effect the party must authorize — settlement-service activation, the quote's DvpProposal pair, deposit accepts, withdrawals, allocations — lands here as 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 expires after 10 minutes if unsigned and is simply dropped from this list (the flow that needed it re-drives, e.g. by re-quoting). Empty for makers whose key the desk holds.

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

{  "actions": [    {      "id": "string",      "purpose": "user-service",      "description": "Sign your quote 97300.0 (2/2: swap proposal)",      "hash": "string",      "tradeId": "string",      "createdAt": "2019-08-24T14:15:22Z",      "expiresAt": "2019-08-24T14:15:22Z"    }  ]}

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