switch frontend to preact

frontend/src/app.tsx

@@ -0,0 +1,20 @@
+import { Provider } from "react-redux";
+import { CssBaseline } from "@mui/material";
+
+import store from "$lib/store";
+import Layout from "$components/layout";
+
+import DefaultHead from "./DefaultHead";
+
+export default function App() {
+	return (
+		<>
+			<CssBaseline>
+				<Provider store={store}>
+					<DefaultHead />
+					<Layout />
+				</Provider>
+			</CssBaseline>
+		</>
+	);
+}