Retire obsolete collection identity before replacement agreement

docs/roadmap/remediation.md

@@ -435,7 +435,16 @@ Validation:
 
 ## 12. Complete Identity Retirement Across Replacement Shapes — P2
 
-Status: [ ] Open.
+Status: [x] Complete.
+
+Completion: source composition and inheritance now prepare eligible lower policy
+from actual replacement paths before agreement. Removed identity and record state
+cannot constrain a new pending key or reappear in later inheritance. Shared mode
+selection preserves explicit-mode persistence and authoritative registrations.
+Regressions cover null/scalar/mapping/list replacement, ancestor removal with a
+new key, reintroduction, and retained/application-constrained conflicts. Verified
+focused retirement/inheritance tests, engine ownership race coverage, and
+`./scripts/check.sh`.
 
 Owners: [`resolveStrictCollectionPolicies`](../../internal/engine/compose.go),
 especially its `sequencePresent` reset condition;