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/public/icon.svg

@@ -0,0 +1,11 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 48 48" width="48" height="48">
+  <defs>
+    <linearGradient id="g" x1="0" y1="0" x2="1" y2="1">
+      <stop offset="0" stop-color="#3d6bff" />
+      <stop offset="1" stop-color="#6a8dff" />
+    </linearGradient>
+  </defs>
+  <rect x="4" y="4" width="40" height="40" rx="12" fill="url(#g)" />
+  <circle cx="24" cy="24" r="10" fill="#0c0c0c" />
+  <circle cx="24" cy="24" r="4" fill="#f5f5f7" />
+</svg>