Implement multi-domain SEO improvements:

- Add metadata to login and login-verify pages to prevent indexing.
- Update robots.txt to disallow additional sensitive paths.
- Enhance sitemap generation to filter by city and include accurate last modified dates.
- Refactor canonical URL generation to support multi-domain architecture, ensuring self-canonicalization for city domains.
- Remove deprecated CanonicalHandler component and streamline canonical URL handling.
- Introduce safe JSON-LD output to prevent XSS vulnerabilities.
- Add payment layout with appropriate metadata to prevent indexing.
- Conduct a comprehensive technical SEO audit and implement necessary fixes across the application.

app/blog/[slug]/page.js

@@ -1,11 +1,14 @@
 import { cache } from "react";
 import BlogPage from "@/components/blog";
 import Layout from "@/components/layout/StLayout";
+import { notFound } from "next/navigation";
 import { fetchReq } from "@/lib/req";
 import { getStateInfo } from "@/lib/getStateInfo";
+import { getRequestOrigin } from "@/lib/getCanonicalUrl";
+import { safeJsonLd } from "@/lib/sanitize";
 import { normalizeBlog, imageUrl } from "@/helper";
 
-const FALLBACK_IMG = "https://www.nobat724.com/assets/images/logo.png";
+const FALLBACK_IMG = "https://nobat724.com/assets/images/logo.png";
 const API_URL = process.env.NEXT_PUBLIC_API_URL;
 
 const getBlog = cache(async (slug) => {
@@ -40,6 +43,8 @@ export async function generateMetadata({ params }) {
     return {
       title,
       description,
+      // محتوای بلاگ روی همه‌ی دامنه‌های شهری یکسان است — تجمیع اعتبار روی دامنه‌ی اصلی
+      alternates: { canonical: `https://nobat724.com/blog/${slug}` },
       openGraph: {
         title,
         description,
@@ -63,8 +68,10 @@ export async function generateMetadata({ params }) {
 
 async function Blog({ params }) {
   const { slug } = await params;
+  const origin = await getRequestOrigin();
 
   const blog = normalizeBlog(await getBlog(slug));
+  if (!blog) notFound();
 
   let relatedBlogs = [];
   const relatedResponse = await fetchReq(
@@ -93,8 +100,8 @@ async function Blog({ params }) {
         "@context": "https://schema.org",
         "@type": "BreadcrumbList",
         itemListElement: [
-          { "@type": "ListItem", position: 1, name: "خانه", item: "https://www.nobat724.com" },
-          { "@type": "ListItem", position: 2, name: "مقالات", item: "https://www.nobat724.com/blogs" },
+          { "@type": "ListItem", position: 1, name: "خانه", item: origin },
+          { "@type": "ListItem", position: 2, name: "مقالات", item: `${origin}/blogs` },
           { "@type": "ListItem", position: 3, name: blog.title },
         ],
       }
@@ -105,13 +112,13 @@ async function Blog({ params }) {
       {jsonLd && (
         <script
           type="application/ld+json"
-          dangerouslySetInnerHTML={{ __html: JSON.stringify(jsonLd) }}
+          dangerouslySetInnerHTML={{ __html: safeJsonLd(jsonLd) }}
         />
       )}
       {breadcrumbJsonLd && (
         <script
           type="application/ld+json"
-          dangerouslySetInnerHTML={{ __html: JSON.stringify(breadcrumbJsonLd) }}
+          dangerouslySetInnerHTML={{ __html: safeJsonLd(breadcrumbJsonLd) }}
         />
       )}
       <Layout>