Handle companion imports without a filesystem base

docs/roadmap/implementation.md

@@ -129,6 +129,8 @@ selection, and diagnostic tests for verification.
 
 ## Stage 4 — Finish companion handling when no base exists
 
+**Status:** Complete. Focused no-base, import, placement, and grouped-load checks passed.
+
 Handle the no-base outcome only for an active underlay binding with no
 override, usable main context, or fallback. `RequireBase` fails with
 `CodeOptionsInvalid` regardless of import enablement or declaration count.