Improve SEO metadata and structured data

app/robots.ts

@@ -1,4 +1,5 @@
-import type { MetadataRoute } from "next";
+import type { MetadataRoute } from "next";
+import { absoluteUrl, siteUrl } from "@/data/site-config";
 
 export default function robots(): MetadataRoute.Robots {
   return {
@@ -6,6 +7,7 @@ export default function robots(): MetadataRoute.Robots {
       userAgent: "*",
       allow: "/",
     },
-    sitemap: "https://grace-salamoun-architect.vercel.app/sitemap.xml",
+    host: siteUrl,
+    sitemap: absoluteUrl("/sitemap.xml"),
   };
 }