- Rename shop-api-reference.md to storefront-api-reference.md
- Update all /api/v1/shop paths to /api/v1/storefront
- Add cart, catalog, checkout modules to module-system.md
- Update API index to reference Storefront API
- Mark Phase 7 as complete in PLAN document
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
