docs: add consolidated dev URL reference and migrate /shop to /storefront

- Add Development URL Quick Reference section to url-routing overview
  with all login URLs, entry points, and full examples
- Replace /shop/ path segments with /storefront/ across 50 docs files
- Update file references: shop_pages.py → storefront_pages.py,
  templates/shop/ → templates/storefront/, api/v1/shop/ → api/v1/storefront/
- Preserve domain references (orion.shop) and /store/ staff dashboard paths
- Archive docs left unchanged (historical)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docs/api/error-handling.md

@@ -167,7 +167,7 @@ Returns JSON error responses suitable for API clients.
 ### Admin/Store Dashboard (`/admin/*`, `/store/*`)
 Returns JSON errors or redirects to error pages based on accept headers.
 
-### Shop Requests (`/shop/*`)
+### Storefront Requests (`/storefront/*`)
 Returns themed error pages matching the store's shop design.
 
 ## Logging