dev.cocore.compute.verifyReceipt

Verify an indexed receipt offline-equivalently: structural checks against its job + attestation, a P-256 ECDSA signature check of `enclaveSignature` against the attestation public key, lexicon-schema validation, and — when an MDA cert chain is present — a hardware-attestation check bound to the signing key. `trustLevel` rises to `hardware-attested` only when a valid Apple chain certifies the receipt-signing key.