Balances of the key's party

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.