feat(webui): add initial webui with websocket chat flow

webui/src/main.tsx

@@ -0,0 +1,14 @@
+import React from "react";
+import ReactDOM from "react-dom/client";
+
+import App from "./App";
+import "./globals.css";
+
+const root = document.getElementById("root");
+if (!root) throw new Error("root element missing");
+
+ReactDOM.createRoot(root).render(
+  <React.StrictMode>
+    <App />
+  </React.StrictMode>,
+);