Enhance blog metadata and SEO with structured Open Graph data; add sitemap and robots.txt functionality; replace default OG image.

app/robots.tsx

@@ -0,0 +1,15 @@
+import { MetadataRoute } from "next";
+
+export default function robots(): MetadataRoute.Robots {
+  const baseUrl = "https://blog.gabrielkaszewski.dev";
+
+  return {
+    rules: [
+      {
+        userAgent: "*",
+        allow: "/",
+      },
+    ],
+    sitemap: `${baseUrl}/sitemap.xml`,
+  };
+}