Refactor Clash component to use GameModal for game interactions, remove Hello World page, and implement toast notifications for error handling

crypto_clash_frontend/app/layout.tsx

@@ -1,6 +1,7 @@
 import type { Metadata } from "next";
 import { Geist, Geist_Mono } from "next/font/google";
 import "./globals.css";
+import ToastContainer from "./components/ToastContainer";
 
 const geistSans = Geist({
   variable: "--font-geist-sans",
@@ -28,6 +29,7 @@ export default function RootLayout({
         className={`${geistSans.variable} ${geistMono.variable} antialiased`}
       >
         {children}
+        <ToastContainer />
       </body>
     </html>
   );