Create a free wallet proof for a manual purchase or private redelivery

Bind one EOA wallet signature to the purpose, payment references, configured merchant, token, network, service, exact public POST URL and complete JSON body. Standard-x402 first purchases keep their existing payment flow. Both wallet-proof paths require a complete JSON body and only ref query parameters; resolve unsupported requests before paying. Private redelivery is free, requires a fresh proof for each attempt and only reads retained results. Missing results return 409 at the target request and require wallet support; no new provider order is created.