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>

docs/frontend/cdn-fallback-strategy.md

@@ -493,7 +493,7 @@ Content-Security-Policy:
 
 ## Related Documentation
 
-- [Shop Frontend Architecture](shop/architecture.md)
+- [Storefront Architecture](storefront/architecture.md)
 - [Vendor Frontend Architecture](vendor/architecture.md)
 - [Admin Frontend Architecture](admin/architecture.md)
 - [Production Deployment](../deployment/production.md)

docs/frontend/shared/logging.md

@@ -395,7 +395,7 @@ window.LogConfig = {
 
 - [Admin Page Templates](../admin/page-templates.md)
 - [Vendor Page Templates](../vendor/page-templates.md)
-- [Shop Page Templates](../shop/page-templates.md)
+- [Storefront Page Templates](../storefront/page-templates.md)
 
 ---