Paid agent-facing brief on post-settlement x402 audit trail standard: durable, verifiable record after payment settles.

Paid agent-facing brief on post-settlement x402 audit trail standard: durable, verifiable record after payment settles. Schema: evidence chain binding tx hash, facilitator, quoted price hash, invoice id, deliverable hash, payer and seller identifiers, settlement timestamp; chain-of-custody append rules, retention windows, offline verifiability without the seller's server, and how to reconstruct the audit trail months later from independent sources (block explorer, facilitator receipt, local