Module artifact 

Signed, reproducible artifact (#238).

Wraps an AbReport into a portable, tamper-evident attestation. Two guarantees:

1. Reproducibility — determinism_digest is a SHA-256 over the evidence only (task ids, context + answer digests, scores, model fingerprint, stats config, verdict). Timestamps and the build version are excluded, so the same inputs yield the same digest on any machine.
2. Integrity + origin — an Ed25519 signature over the canonical bytes (signature fields cleared) proves the artifact was produced by a specific key and not altered since. This mirrors the established savings_ledger::signed_batch pattern exactly.

Structs

AbVerifyResult

Outcome of verifying a SignedAbReportV1.

SignedAbReportV1

A signed A/B quality attestation.

Functions

default_artifact_path

Default artifact location: <data_dir>/eval/ab-report-v1_<utc-stamp>.json.

determinism_digest

Computes the machine-independent run digest (records sorted by id for a canonical order).

load_artifact

Loads + parses an artifact, rejecting unrelated JSON by kind.

write_artifact

Pretty-prints the artifact to out (creating parent dirs). Returns the written path.