Document main-relative companion loading

docs/roadmap/implementation.md

@@ -227,6 +227,8 @@ incidental call counts.
 
 ## Stage 8 — Document and verify the completed sprint
 
+**Status:** Complete. Focused integration and consumer checks, the everyday checker, the race suite, and changed local-link checks passed.
+
 Update the public declaration comments and the discovery, layered loading,
 imports, resource context and selected overlay sections of
 [the configuration contract](../config.md). Document lookup versus