Agent Action that polls a Relay (Tron) transfer until it reaches a terminal status.

It never signs or moves funds, so it does not authorize a spend. It does reconcile the execute-time budget reservation at a terminal status: a refund releases it (SpendGate.release_by_intent/2, idempotent), any other terminal status forgets the tag while the spend stands. Pass the same :ledger and :agent_id used for the execute for this to take effect. A completed transfer returns {:ok, summary}; a failed or refunded transfer surfaces as {:error, %Failure{}}, never as {:ok, ...}.

Context keys

• :relay_config -- %{base_url:, auth_token:} for Relay.Client.
• :ledger, :agent_id -- optional; the Ledger and key from the execute, so a refund releases that reservation. See SpendGate.