Record Narratio upgrade validation

docs/roadmap/implementation.md

@@ -1,6 +1,6 @@
 # Implementation Plan 0021: Adopt Narratio v3.0.0
 
-Status: in_progress
+Status: implemented — independent review pending
 
 Target executor: GPT-5.6-Terra
 
@@ -192,6 +192,8 @@ Commit as `Test Narratio selectors and credential lists`.
 
 ## Stage 3: Document Upgrade Ownership and Hand Off for Review
 
+Completion: complete (2026-09-28).
+
 ### Required Policy Review
 
 Read workspace `AGENTS.md`, `docs/orientation.md`, `docs/conventions.md`,
@@ -271,6 +273,12 @@ Plan approved.
   explicit empty lists/selectors without synthetic values, and clean immediate
   repeats passed. The older selected-version and supplied-Go cases remained
   valid. Role `git diff --check` passed.
+- Stage 3: role commits `a28f22c`, `45f6836`, and `3c0700b` provide the
+  implementation and upgrade guidance. The README was checked against tagged
+  v3.0.0 release, configuration, integration, and operations contracts.
+  Documentation-only changes reuse Stage 2 behavior evidence; role/workspace
+  `git diff --check` and `scripts/status` passed. F0021 remains open for
+  independent review.
 
 ## Open Questions