docs(scripts): note factory auto-detection in README

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: jcllobet

scripts/find-unused.README.md

@@ -10,7 +10,7 @@ bash scripts/find-unused.sh
 
 Requires `npx` (knip is fetched automatically). A fake `DATABASE_URL` is injected so config resolution doesn't fail.
 
-The script auto-detects the factory root (`../../..`) and all sibling repos for cross-referencing.
+The script auto-detects whether it's running inside a factory layout (`../../.._repos/`). When inside a factory, it cross-references sibling repos. When standalone, it skips sibling checks gracefully and still runs all internal checks.
 
 ## What it does