feat: scaffold frontend app structure

frontend/src/app/router.tsx

@@ -0,0 +1,15 @@
+import { createBrowserRouter } from "react-router-dom";
+import { AppLayout } from "./layouts/AppLayout";
+import { DashboardPage } from "../pages/DashboardPage";
+import { RacesPage } from "../pages/RacesPage";
+
+export const appRouter = createBrowserRouter([
+  {
+    path: "/",
+    element: <AppLayout />,
+    children: [
+      { index: true, element: <DashboardPage /> },
+      { path: "races", element: <RacesPage /> }
+    ]
+  }
+]);