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.

lib/specialtyContent.test.js

@@ -0,0 +1,63 @@
+import { describe, expect, it } from "vitest";
+import { buildSpecialtyFaq, buildSpecialtyIntro } from "@/lib/specialtyContent";
+import { buildClinicsIntro, buildDoctorsIntro } from "@/lib/listingIntro";
+
+const words = (text) => text.trim().split(/\s+/).length;
+
+const CITIES = ["تهران", "یاسوج", "یزد", "تبریز", "اصفهان", "مشهد", "ایران"];
+const SPECIALTIES = ["پوست و مو", "قلب و عروق", "داخلی", "اطفال"];
+
+describe("متن مقدمهٔ تخصص (M2)", () => {
+  it("هر ترکیب تخصص/شهر بین ۱۵۰ تا ۳۰۰ کلمه است", () => {
+    for (const specialty of SPECIALTIES) {
+      for (const city of CITIES) {
+        const count = words(buildSpecialtyIntro(specialty, city, 12));
+        expect(count, `${specialty}/${city} = ${count}`).toBeGreaterThanOrEqual(150);
+        expect(count, `${specialty}/${city} = ${count}`).toBeLessThanOrEqual(300);
+      }
+    }
+  });
+
+  it("متن شهرهای مختلف یکسان نیست", () => {
+    const texts = CITIES.map((city) => buildSpecialtyIntro("پوست و مو", city, 5));
+    expect(new Set(texts).size).toBe(CITIES.length);
+  });
+
+  it("خروجی پایدار است (بین دو فراخوانی تغییر نمی‌کند)", () => {
+    expect(buildSpecialtyIntro("داخلی", "یزد", 3)).toBe(buildSpecialtyIntro("داخلی", "یزد", 3));
+  });
+});
+
+describe("متن مقدمهٔ صفحات لیست (M2)", () => {
+  it("بین ۱۵۰ تا ۳۰۰ کلمه", () => {
+    for (const city of CITIES) {
+      for (const text of [buildDoctorsIntro(city), buildClinicsIntro(city)]) {
+        expect(words(text), `${city} = ${words(text)}`).toBeGreaterThanOrEqual(100);
+        expect(words(text), `${city} = ${words(text)}`).toBeLessThanOrEqual(300);
+      }
+    }
+  });
+
+  it("ساختار متن بین شهرها متفاوت است", () => {
+    const texts = CITIES.map(buildDoctorsIntro);
+    expect(new Set(texts).size).toBe(CITIES.length);
+  });
+});
+
+describe("سوالات متداول تخصص (M1)", () => {
+  it("هر سوال متن پاسخ دارد", () => {
+    const faq = buildSpecialtyFaq("قلب و عروق", "تهران", 7);
+    expect(faq.length).toBeGreaterThanOrEqual(4);
+    for (const item of faq) {
+      expect(item.question).toBeTruthy();
+      expect(item.answer.length).toBeGreaterThan(30);
+    }
+  });
+
+  it("تعداد پزشک صفر، جملهٔ متفاوت می‌سازد", () => {
+    const withCount = buildSpecialtyFaq("داخلی", "یزد", 9)[1].answer;
+    const without = buildSpecialtyFaq("داخلی", "یزد", 0)[1].answer;
+    expect(withCount).not.toBe(without);
+    expect(withCount).toContain("9");
+  });
+});