ddg-payment-rail-verify@1.0.0

Publisher claims: "Prove an agent's payment path still works end to end and keep proving it: a paid smoke test, a 402-envelope pre-flight, and a buyer-side trust probe of the seller you depend on. Use before going live, after changing a wallet or SDK, and as a weekly canary. Receipt verification is free." Observed in sandbox: no network, touches nothing outside the project, writes no memory.