V2-03: Freeze evidence schema v2 and the detached signature manifest

[DevFoundry-labs]

Outcome

Freeze a portable evidence format that separately establishes byte integrity, trusted signing origin, and control assurance quality.

Contract requirements

• Define allowlisted evidence schema v2 and stable collection/timestamp ordering.
• Freeze canonical UTF-8 bytes and completion-event cutoff behavior.
• Define a domain-separated signing statement containing evidence digest, case ID, schema version, completion event hash, and key ID.
• Use Ed25519 with a detached deterministic manifest.
• Require an operator-supplied trusted public key or pinned fingerprint by default.
• Define signed, unsigned, legacy-v1, digest-mismatch, signature-failure, and trust-anchor-mismatch results.
• Define key loading, rotation, encrypted-key behavior, and signing-required failure semantics.
• Freeze CLI exit codes and machine-readable output.
• Publish cross-platform golden evidence/signature vectors and tamper cases.

Acceptance criteria

• A verifier can validate transferred evidence without database access.
• A bundled public key is never silently treated as trusted origin.
• Historical evidence remains verifiable after key rotation.
• Re-export at the same completion cutoff produces identical evidence bytes.
• Private signing material cannot enter SQLite, logs, evidence, fixtures, or distributions.
• Evidence v1 remains readable and is accurately labeled legacy_digest_only.

Planning source

.dev/v2/EVIDENCE_V2_SPEC.md.

Dependencies

Blocked by #8. Pilot evidence-consumer and key-ownership findings must be reflected before implementation issues open.