fix: use export default in proxy.js for Next.js 16 middleware detection

Next.js 16 requires a default export to register middleware. The named
re-export produced an empty middleware manifest, so the auth guard never
ran and the dashboard showed a white "Loading..." page.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/proxy.js

@@ -1,4 +1,8 @@
-export { proxy } from "./dashboardGuard";
+import { proxy as dashboardProxy } from "./dashboardGuard";
+
+export default async function proxy(request) {
+  return dashboardProxy(request);
+}
 
 export const config = {
   matcher: ["/((?!_next/static|_next/image|favicon\\.ico).*)"],