Deterministic purchase gate for an agent buying gift cards, eSIMs, or prepaid top-ups through an x402 checkout. Ordered

Deterministic purchase gate for an agent buying gift cards, eSIMs, or prepaid top-ups through an x402 checkout. Ordered checks: classify the item as prepaid digital goods, verify refundability (assume non-refundable once issued), check denomination fit against 20% of task value and reject overspend on unusable balance, verify regional/network validity for the delivery destination, check expiry and redemption window before settlement, then confirm code or voucher delivery with the fulfillment