feat: integrate Firebase Cloud Messaging for push notifications

app/ClientLayout.js

@@ -41,6 +41,7 @@ import { motion, AnimatePresence } from "framer-motion";
 import AuthService from "./services/AuthService";
 import { UserRole, UserRoleLabels } from "./enums/UserRole";
 import "./i18n/config";
+import NotificationHandler from "./components/NotificationHandler";
 
 export default function ClientLayout({ children }) {
   const { t, i18n } = useTranslation();
@@ -798,6 +799,7 @@ export default function ClientLayout({ children }) {
           </div>
         </footer>
       )}
+      <NotificationHandler />
     </>
   );
 }