Lists callback requests for a specific call center.

Returns a paginated list of callback requests in the specified call center that the API key has access to. Callbacks are returned in FIFO order
(oldest first), so the first callback in the list has been waiting longest. Each callback includes a status field indicating whether it is 'queued' (actively waiting for fulfillment) or 'timed_out' (exceeded the call center's max_hold_seconds). Timed-out callbacks have queue_position set to null. Requires admin-level access to the call center.

Authorization: API key must have admin access to the specified call center.

Rate limit: 1200 per minute.