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/[slug]/page.js

@@ -0,0 +1,135 @@
+import { notFound } from "next/navigation";
+import Layout from "@/components/layout/StLayout";
+import SpecialtyDetailPage from "@/components/specialties/detail";
+import specialtiesData from "@/data/specialties.json";
+import { getStateInfo } from "@/lib/getStateInfo";
+import { getRequestOrigin } from "@/lib/getCanonicalUrl";
+import { resolveCityDisplayName } from "@/lib/domainHelpers";
+import { buildSpecialtyFaq, buildSpecialtyIntro } from "@/lib/specialtyContent";
+import { safeJsonLd } from "@/lib/sanitize";
+import { fetchReq } from "@/lib/req";
+
+const API_URL = process.env.NEXT_PUBLIC_API_URL;
+const DOCTOR_LIMIT = 12;
+
+const findSpecialty = (slug) =>
+  specialtiesData.find((item) => item.slug === slug && item.status === 1) ?? null;
+
+// روی هر دامنهٔ شهری این صفحه خودکار «تخصص + همان شهر» است — شهر از host می‌آید.
+async function getDoctors(specialtyId, cityId) {
+  try {
+    const res = await fetchReq(`${API_URL}/api/v1/doctors`, {
+      params: {
+        specialty_id: specialtyId,
+        ...(cityId && { city_id: cityId }),
+        page: 1,
+        limit: DOCTOR_LIMIT,
+      },
+    });
+    return {
+      items: res?.data?.data ?? res?.data ?? [],
+      total: Number(res?.data?.meta?.totalRecords ?? res?.meta?.totalRecords ?? 0),
+    };
+  } catch {
+    return { items: [], total: 0 };
+  }
+}
+
+export async function generateMetadata({ params }) {
+  const { slug } = await params;
+  const specialty = findSpecialty(slug);
+  if (!specialty) notFound();
+
+  const { matchedCity, isRoot } = await getStateInfo();
+  const siteName = matchedCity?.site_name || "نوبت 724";
+  const cityName = resolveCityDisplayName(isRoot ? null : matchedCity);
+
+  const title = `متخصص ${specialty.name} در ${cityName} | رزرو نوبت آنلاین | ${siteName}`;
+  const description = `لیست بهترین پزشکان ${specialty.name} در ${cityName} همراه با نشانی مطب، ساعات کاری و امتیاز بیماران. رزرو نوبت آنلاین متخصص ${specialty.name}.`;
+  const image = "/assets/images/og-image.png";
+
+  return {
+    title,
+    description,
+    // C1-a — صفحهٔ فرود تخصص per-domain است؛ canonical لایهٔ layout (self) درست است.
+    openGraph: { title, description, images: [image] },
+    twitter: { card: "summary_large_image", title, description, images: [image] },
+  };
+}
+
+async function SpecialtyDetail({ params }) {
+  const { slug } = await params;
+  const specialty = findSpecialty(slug);
+  if (!specialty) notFound();
+
+  const { matchedCity, isRoot } = await getStateInfo();
+  const origin = await getRequestOrigin();
+  const cityName = resolveCityDisplayName(isRoot ? null : matchedCity);
+
+  const { items: doctors, total } = await getDoctors(
+    specialty.id,
+    isRoot ? null : matchedCity?.id
+  );
+
+  const intro = buildSpecialtyIntro(specialty.name, cityName, total);
+  const faq = buildSpecialtyFaq(specialty.name, cityName, total);
+  const pageUrl = `${origin}/specialties/${specialty.slug}`;
+
+  const pageJsonLd = {
+    "@context": "https://schema.org",
+    "@type": "MedicalWebPage",
+    "@id": `${pageUrl}#webpage`,
+    url: pageUrl,
+    name: `متخصص ${specialty.name} در ${cityName}`,
+    description: intro.slice(0, 300),
+    about: { "@type": "MedicalSpecialty", name: specialty.name },
+    ...(doctors.length > 0 && {
+      mainEntity: {
+        "@type": "ItemList",
+        numberOfItems: doctors.length,
+        itemListElement: doctors.map((doctor, idx) => ({
+          "@type": "ListItem",
+          position: idx + 1,
+          url: `${origin}/doctor/${doctor.uuid}`,
+          name: doctor.name,
+        })),
+      },
+    }),
+  };
+
+  // FAQPage عمداً یک script مستقل است تا اسکیماهای موجود صفحه را نشکند.
+  const faqJsonLd = {
+    "@context": "https://schema.org",
+    "@type": "FAQPage",
+    mainEntity: faq.map((item) => ({
+      "@type": "Question",
+      name: item.question,
+      acceptedAnswer: { "@type": "Answer", text: item.answer },
+    })),
+  };
+
+  return (
+    <>
+      <script
+        type="application/ld+json"
+        dangerouslySetInnerHTML={{ __html: safeJsonLd(pageJsonLd) }}
+      />
+      <script
+        type="application/ld+json"
+        dangerouslySetInnerHTML={{ __html: safeJsonLd(faqJsonLd) }}
+      />
+      <Layout name="/specialties">
+        <SpecialtyDetailPage
+          specialtyName={specialty.name}
+          cityName={cityName}
+          doctors={doctors}
+          intro={intro}
+          faq={faq}
+          origin={origin}
+        />
+      </Layout>
+    </>
+  );
+}
+
+export default SpecialtyDetail;

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}`;