feat: add canonical URL handling and entity quality checks

- Implemented canonical URL strategies for city-specific domains and entities.
- Added helper functions for domain and city resolution.
- Created tests for canonical URL generation and domain resolution.
- Introduced entity quality checks for doctors and clinics to ensure meaningful content.
- Developed unique introductory texts for listing pages to avoid duplicate content.
- Established robots.txt policies for listing pages to manage indexing based on user filters.
- Enhanced specialty content with dynamic introductions and FAQs to improve SEO.

proxy.js

@@ -5,6 +5,8 @@ export function proxy(request) {
 
     // Add pathname to headers so we can access it in getCanonicalUrl
     response.headers.set('x-pathname', request.nextUrl.pathname);
+    // canonical صفحات لیست به pagination وابسته است، ولی layout به searchParams دسترسی ندارد
+    response.headers.set('x-search', request.nextUrl.search || '');
 
     return response;
 }