Constant EVENT_TYPE_ARTIFACT_ATTESTED 

pub const EVENT_TYPE_ARTIFACT_ATTESTED: &str = "artifact_attested";

Event type binding an out-of-chain artifact to a chain event by content hash (v0.8). Required payload fields: artifact_hash (algorithm-prefixed canonical hash), bound_event_id, artifact_kind (free-form string, e.g. legible_record, session_recording). Artifacts are advisory; the chain event is authoritative.