Approve Credit Hold

The customer service supervisor approves a credit OR A REFUND that was held for being past the customer's total, and it is sent (Frederick, 2026-10-07, issue #3757: "No customer service supervisor is mark"). 403 not_the_supervisor for anyone else, 409 not_waiting when it was already decided (nothing is sent twice), and the same Pigeonly answers as any credit or refund when the send itself is refused. A refund whose invoice can no longer be refunded (it was refunded meanwhile) fails plainly with 422 and nothing is sent. Called by the Today card. (The path keeps the name it had when only credits were held, so the reviewed API and its callers did not move; OPEN_ITEMS REF-8.)