Re-verify any exhibit402 proof-of-publication certificate for $0.02. Pass id = ERC-721 token id, Arweave tx id, or job id. The service re-downloads the permanently stored screenshot and signed manifest, recomputes every SHA-256, and checks them against the manifest and the on-chain record (immutable screenshotSha256, tokenURI, owner). Returns a machine-readable verdict with per-check detail, so an agent can confirm a certificate is genuine without trusting the issuer.