Migrate app to Node Electron with modern React UI

src/renderer/main.tsx

@@ -0,0 +1,15 @@
+import React from "react";
+import { createRoot } from "react-dom/client";
+import { App } from "./App";
+import "./styles.css";
+
+const rootElement = document.getElementById("root");
+if (!rootElement) {
+  throw new Error("Root element fehlt");
+}
+
+createRoot(rootElement).render(
+  <React.StrictMode>
+    <App />
+  </React.StrictMode>
+);