06 - BLOCKER E: Rollback Source Artifact Fix (sealed evidence_registry body)

Codex recheck finding

source_sha256 (and the #27 rollback_stub_source_sha256) is proof of a body, not the body or a restore mechanism. It cannot restore a function/procedure definition unless the full source artifact is present and sealed. Every body-changing action (STUB_FAIL_CLOSED) must bind a content-addressed, read-back-verified source artifact and the exact authorized restore operation. (Codex recheck CHECK_C issue 2 / CHECK_E.)

Ground truth - the approved evidence_registry already stores content-addressed artifacts

From the approved DDL (codex-fix7-spec-artifact-correction-.../09 CP-08):

CREATE TABLE qt001_cp.evidence_registry (
  evidence_id uuid PRIMARY KEY,
  evidence_kind_id uuid NOT NULL REFERENCES qt001_cp.code_catalog_item(item_id),
  storage_class_item_id uuid NOT NULL REFERENCES qt001_cp.storage_class_manifest(item_id),
  artifact_uri      qt001_cp.nonempty_text NOT NULL,   -- KB doc id / object-store URI of the BODY
  artifact_sha256   qt001_cp.sha256 NOT NULL,          -- content hash
  artifact_size_bytes qt001_cp.nonnegative_bigint NOT NULL,
  issuer_principal_id uuid NOT NULL,
  control_epoch ..., issued_at ..., last_readback_at timestamptz NOT NULL,
  valid_until timestamptz NOT NULL, revoked_at timestamptz NULL,
  supersedes_evidence_id uuid NULL ...,
  UNIQUE(storage_class_item_id,artifact_uri,artifact_sha256), CHECK(valid_until>issued_at));

artifact_uri is exactly Codex's "source artifact path or KB document ID"; artifact_sha256 is the content hash; last_readback_at proves read-back verification.

The fix - STUB body restore = sealed evidence_registry artifact (docs 02, 04, 05, 06)

For every STUB_FAIL_CLOSED member, the blueprint binds, in addition to the #27 hash:

• source artifact reference = evidence_registry.artifact_uri (KB doc ID / object-store URI) of the prior legacy body AND of the fail-closed stub;
• source artifact sha256 = evidence_registry.artifact_sha256, which MUST equal the pinned #27 old_source_sha256 / rollback_stub_source_sha256;
• object identity / owner / language / argument signature = from the #20 row (object_identity = regprocedure incl. argument types; expected_owner_role; object_type);
• read-back verification = last_readback_at set; the artifact content is fetched and its sha256 recomputed.

Authorized restore operation: fetch the artifact_uri body → verify its sha256 == artifact_sha256 == the pinned #27 hash → operator CREATE OR REPLACE of the legacy object (a separate, authorized operator function-replacement of a legacy object - different object class from the never-overwritten gateway, Codex CR-E3) → verify the live pg_get_functiondef sha256 == the pinned #27 hash. The final authority that the restore succeeded is PG-native (the post-restore live hash match), with the KB/object-store artifact as the source material.

Fallback rule: if the prior body is not available as a sealed, read-back-verified evidence_registry artifact, the body change is not allowed - the object is dispositioned REVOKE_ONLY + owner isolation instead of STUB_FAIL_CLOSED. A body change with no restorable source is forbidden.

Self-check

PASS only if every body-changing action has a real, sealed, read-back-verified source artifact and an authorized restore that verifies the restored hash. PASS - STUB bodies are content-addressed evidence_registry artifacts (URI + sha256 == #27 hash), restored by an authorized operator replacement verified against the pinned hash; no-artifact ⇒ no body change.