Check the current status of a purchase request. Read-only: it never issues, draws, or reveals a card. Returns the status (and the denial reason when denied). When approved, it reports a retrievable boolean: true means the single-use card has not been drawn yet, so call retrieve_card ONCE when you are ready to pay; false means the card was already retrieved and cannot be shown again (start a new purchase if you need another). While pending_review it returns review_url, the page where a human approves or denies — relay that link to the person if they ask where the request is. Safe to poll while a request is pending_review or processing.