Compose AI artifact ref sets

Author: nshkrdotcom

.blitz/test_state_v1/indexes/task_states.ndjson

@@ -4,3 +4,9 @@ Ref-only adaptive artifact contracts for prompt, role, candidate, router,
 verifier, eval, replay, provider, endpoint, promotion, and rollback identity.
 The package never carries raw prompts, provider payloads, model outputs, memory
 bodies, credential material, or non-OuterBrain skill ownership.
+
+Use `OuterBrain.AIArtifactContracts.build_ref_set/1` to construct the composed
+proof/reporting view. The returned `RefSet` groups refs by concern:
+`prompt_refs`, `optimization_refs`, `evaluation_refs`, `routing_refs`, and
+`model_refs`. Use `policy_artifact_ref/1` for policy artifacts that carry
+source, lineage, rollback, trace, and redaction refs.