refactor(customers): migrate routes to module with auto-discovery

- Move customer route implementations to app/modules/customers/routes/
- Convert legacy app/api/v1/{admin,vendor}/customers.py to re-exports
- Update router registrations to use module routers with access control
- Fix CustomerListResponse pagination (page/per_page/total_pages)
- Update URL routing docs to use storefront consistently
- Fix mkdocs.yml nav references (shop -> storefront)
- Fix broken doc links in logging.md and cdn-fallback-strategy.md

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

mkdocs.yml

@@ -64,7 +64,7 @@ nav:
     # --- API Reference ---
     - API Reference:
       - Overview: api/index.md
-      - Shop API Reference: api/shop-api-reference.md
+      - Storefront API Reference: api/storefront-api-reference.md
       - Authentication:
         - Guide: api/authentication.md
         - Quick Reference: api/authentication-quick-reference.md
@@ -106,12 +106,12 @@ nav:
       - Vendor Frontend:
         - Architecture: frontend/vendor/architecture.md
         - Page Templates: frontend/vendor/page-templates.md
-      - Shop Frontend:
-        - Architecture: frontend/shop/architecture.md
-        - Page Templates: frontend/shop/page-templates.md
-        - E-commerce Components Proposal: frontend/shop/ecommerce-components-proposal.md
-        - Authentication Pages: frontend/shop/authentication-pages.md
-        - Navigation Flow: frontend/shop/navigation-flow.md
+      - Storefront:
+        - Architecture: frontend/storefront/architecture.md
+        - Page Templates: frontend/storefront/page-templates.md
+        - E-commerce Components Proposal: frontend/storefront/ecommerce-components-proposal.md
+        - Authentication Pages: frontend/storefront/authentication-pages.md
+        - Navigation Flow: frontend/storefront/navigation-flow.md
 
     # --- Development ---
     - Development: