Enforce signed backup evidence before migrations

docs/RECOVERY_AND_ROLLBACK_GUARANTEES.md

@@ -98,11 +98,15 @@ old code may not understand the new schema. Recovery then means one of:
 3. restore a separately verified, coordinated database/object/key backup and
    then deploy the matching release.
 
-The deployment tool does not create or validate that database backup. A
-`backup-required` annotation on the Kubernetes migration Job is an operator
-gate, not backup evidence. Production automation must provide a backup hook or
-external backup controller whose artifact, timestamp, scope, encryption key,
-and restore test can be referenced from the recovery record.
+The deployment tool does not create that backup. It does verify an externally
+produced, signed evidence contract covering PostgreSQL, objects, protected
+configuration, and key custody at one recovery point plus an isolated restore
+drill. A self-hosted release change cannot reach the migration command or be
+exported as a Kubernetes migration Job until fresh evidence bound to the
+previous immutable release has been adopted. Compose verifies it again after
+runtime quiescing. See
+[Backup And Restore Evidence](BACKUP_AND_RESTORE_EVIDENCE.md) for the contract,
+provider runbooks, RPO/RTO ownership, retention, and disposal rules.
 
 ## Scaled Nodes