Code Migration

Core principle: When you move responsibility from A to B, delete A.

Half-migrations are technical debt. If files_helper.py and path_comp.py both construct paths, every developer must learn which one to use. That ambiguity is the bug.

Migration Checklist

When moving logic from one location to another:

• Move the code to its canonical location
• Update all call sites (use grep, not hope)
• Update skills that reference the old location
• Add ruff rules to ban imports from the old location
• Delete the old code (not deprecate - delete)
• Run validate_skills.py to catch stale references
• Run tests to confirm nothing broke