feat(web): service-worker notifications and composer/scroll UX fixes

- register notifications service worker and handle click-to-open chat/message

- route realtime notifications through service worker with fallback

- support ?chat=&message= deep-link navigation in chats page

- enforce 1s minimum voice message length

- lift scroll-to-bottom button to avoid overlap with composer action

web/src/main.tsx

@@ -2,8 +2,11 @@ import React from "react";
 import ReactDOM from "react-dom/client";
 import { App } from "./app/App";
 import { AppErrorBoundary } from "./components/AppErrorBoundary";
+import { registerNotificationServiceWorker } from "./utils/webNotifications";
 import "./index.css";
 
+void registerNotificationServiceWorker();
+
 ReactDOM.createRoot(document.getElementById("root")!).render(
   <React.StrictMode>
     <AppErrorBoundary>