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.

app/specialties/page.js

@@ -3,9 +3,10 @@ import SpecialtiesPage from "@/components/specialties";
 import { getStateInfo } from "@/lib/getStateInfo";
 
 export async function generateMetadata() {
-  const { matchedCity } = await getStateInfo();
+  const { matchedCity, isRoot } = await getStateInfo();
   const siteName = matchedCity?.site_name || "نوبت 724";
-  const cityName = matchedCity?.name || "";
+  // روی دامنهٔ ریشه نام رکورد («نوبت 724») برند است نه شهر — نباید در Title بنشیند.
+  const cityName = isRoot ? "" : matchedCity?.name || "";
   const title = cityName
     ? `تخصص‌های پزشکی در ${cityName} | ${siteName}`
     : `تخصص‌های پزشکی | ${siteName}`;