Proof Receipt Expiry Appeal

This mechanic treats a receipt as a scoped proof carrier with an appeal window, not a permanent clean flag. Once expiry is visible, route readers must consume the appeal posture before using the receipt.

Required fields: source_receipt_row, receipt_holder, appeal_deadline, proof_carrier_or_absence, affected_future_reader, requested_route_use, expiry_state, accepted_cost_or_absence, and future_route_effect.

Accepted postures are certify_limited_receipt, escrow_receipt_carrier, reopen_appeal_window, convert_to_route_debt, quarantine_expired_receipt, and expired_proof_default.