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/index.html

@@ -0,0 +1,16 @@
+<!doctype html>
+<html lang="zh-CN">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0, viewport-fit=cover" />
+    <meta name="theme-color" content="#161616" />
+    <meta name="description" content="Cyrene v2 用户前端（M9 模态 UI）" />
+    <link rel="manifest" href="/manifest.json" />
+    <link rel="icon" type="image/svg+xml" href="/icon.svg" />
+    <title>Cyrene · 昔涟</title>
+  </head>
+  <body>
+    <div id="root"></div>
+    <script type="module" src="/src/main.tsx"></script>
+  </body>
+</html>