seo: add sitemap.ts

src/app/sitemap.ts

@@ -0,0 +1,12 @@
+import { MetadataRoute } from "next";
+
+export default function sitemap(): MetadataRoute.Sitemap {
+  return [
+    {
+      url: "https://www.wilddragon.net",
+      lastModified: new Date(),
+      changeFrequency: "monthly",
+      priority: 1,
+    },
+  ];
+}