feat(web): complete MVP0 public layout, banner, and SEO baseline

apps/web/src/app/sitemap.ts

@@ -0,0 +1,14 @@
+import type { MetadataRoute } from "next"
+
+const baseUrl = process.env.CMS_WEB_ORIGIN ?? "http://localhost:3000"
+
+const publicRoutes = ["/", "/about", "/contact"]
+
+export default function sitemap(): MetadataRoute.Sitemap {
+  const now = new Date()
+
+  return publicRoutes.map((route) => ({
+    url: `${baseUrl}${route}`,
+    lastModified: now,
+  }))
+}