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/index.md

@@ -68,8 +68,8 @@ admin.platform.com    → Admin Interface
 
 **3. Path-Based Mode** (Development Only)
 ```
-platform.com/stores/store1/shop  → Store 1 Shop
-platform.com/stores/store2/shop  → Store 2 Shop
+platform.com/storefront/store1  → Store 1 Shop
+platform.com/storefront/store2  → Store 2 Shop
 platform.com/admin                 → Admin Interface
 ```