feat: implement chat interface and registration modal

frontend/src/App.tsx

@@ -1,10 +1,11 @@
 import "./App.css";
 import Layout from "./layout/Layout";
+import MainChat from "./components/MainChat";
 
 function App() {
   return (
     <Layout>
-      <h1>Hello World</h1>
+      <MainChat />
     </Layout>
   );
 }