Add Next.js frontends with health endpoints

apps/docs/app/page.tsx

@@ -0,0 +1,11 @@
+export default function Page() {
+  return (
+    <div>
+      <h2>BlackRoad OS – Documentation</h2>
+      <p>
+        This site will contain architecture, API references, and
+        operator playbooks for the BlackRoad Operating System.
+      </p>
+    </div>
+  );
+}