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

apps/web/src/app/robots.ts

@@ -0,0 +1,13 @@
+import type { MetadataRoute } from "next"
+
+const baseUrl = process.env.CMS_WEB_ORIGIN ?? "http://localhost:3000"
+
+export default function robots(): MetadataRoute.Robots {
+  return {
+    rules: {
+      userAgent: "*",
+      allow: "/",
+    },
+    sitemap: `${baseUrl}/sitemap.xml`,
+  }
+}