Implement the engine spine: claim, outbox, machine, API

Contracts first (T02–T04): approval claim schema with issuer, freshness,
and binding digest; local transactional outbox wire; load-bearing cadence
as heartbeat or reconciliation (layer.yaml declared).

Then the object (T06–T08): SQLite closed state machine, CAS supersession,
distinct-approver fail-closed, revocation without holder cooperation,
outbox insert in the same transaction. Tests fail the mutation when
emission fails, and revoke while the drain sink is down.

Introspection GET /v1/approvals/{id}/claim is a PIP fact, not a decision.
No public consume (T05 waits on GH-WP-0002-T06). Canon T-06 coverage for
wrong binding, expiry, revoke, and supersede.

FLEX-WP-0017 T03 is unblocked on this object; T05 remains blocked only on
consumption ordering.

Assistant: grok
Assistant-Session: 01a04ceb-2057-7e20-b0f9-c282964d5dd9

layer.yaml

@@ -39,10 +39,9 @@ approval_validity_query: owned        # current-state introspection, not a verdi
 # audit-core's PostgreSQL custody).
 tooling_contacts: []
 
-# §11: record non-Tooling clients so the check is total. None exist: there
-# is no runtime. Listed targets are the intended Engine APIs and the
-# uncatalogued hub write, to be filled in as code appears rather than
-# discovered later as silence.
+# §11: record non-Tooling clients so the check is total. The SQLite store is
+# this engine's own operational store, not a §4 Tooling row. Drain is a
+# callback; no audit-core client is compiled in.
 non_tooling_clients: []
 
 intended_non_tooling_clients:
@@ -64,9 +63,10 @@ intended_non_tooling_clients:
 # low-volume load-bearing classes is reconciliation or a heartbeat.
 evidence:
   kind: load-bearing
-  atomicity: local-outbox             # required; not yet implemented
+  atomicity: local-outbox
   cadence_form: heartbeat-or-reconciliation
-  cadence_status: undeclared          # APPROVAL-WP-0001-T04
+  cadence_status: declared
+  cadence: cadence.yaml
   residual: adversarial-omission-at-compromised-source
   custody: same-bound-as-every-other-source   # §16 decided: no stronger archive