feat(frontend): M9 模态 UI（mode 系统+共享 store+WS 客户端 + chat(思维链/工具回显/情绪徽标)/code/Agent 监控/后台思考页 + Miuix 设计 token + PWA）；tsc+vite build 通过

frontend/web/src/main.tsx

@@ -0,0 +1,23 @@
+import { StrictMode } from "react";
+import { createRoot } from "react-dom/client";
+import App from "./App";
+import "./styles/index.css";
+
+// PWA: register the service worker (production only — the dev server's caching
+// would otherwise serve stale modules).
+if ("serviceWorker" in navigator && import.meta.env.PROD) {
+  window.addEventListener("load", () => {
+    navigator.serviceWorker.register("/sw.js").catch(() => {
+      // Non-fatal: the app still works without the offline shell.
+    });
+  });
+}
+
+const container = document.getElementById("root");
+if (!container) throw new Error("#root not found");
+
+createRoot(container).render(
+  <StrictMode>
+    <App />
+  </StrictMode>
+);