fix(ui): Copilot 浮窗按钮被 F7 全局 width:100% 撑满，显式覆盖为 width:auto

Framework7 自带 button { width: 100% } 且打包后排在 Copilot 规则之后，把
面板内 ✕ 与发送按钮拉满父容器，input 被挤成 21px、✕ 跑到面板中部。
在 .copilot-close / .copilot-compose button 上显式 width:auto + flex 固定，
重建并同步 backend/static 产物（main.00d05e81.css）。

backend/static/asset-manifest.json

@@ -1,16 +1,16 @@
 {
   "files": {
-    "main.css": "/static/css/main.a0945a9e.css",
-    "main.js": "/static/js/main.56f8eb9b.js",
+    "main.css": "/static/css/main.00d05e81.css",
+    "main.js": "/static/js/main.361d6838.js",
     "static/media/Framework7Icons-Regular.ttf": "/static/media/Framework7Icons-Regular.4b8a7d10ca32f3125696.ttf",
     "static/media/Framework7Icons-Regular.woff": "/static/media/Framework7Icons-Regular.286bd8fcebb566a45853.woff",
     "static/media/Framework7Icons-Regular.woff2": "/static/media/Framework7Icons-Regular.852655880420bcb785bd.woff2",
     "index.html": "/index.html",
-    "main.a0945a9e.css.map": "/static/css/main.a0945a9e.css.map",
-    "main.56f8eb9b.js.map": "/static/js/main.56f8eb9b.js.map"
+    "main.00d05e81.css.map": "/static/css/main.00d05e81.css.map",
+    "main.361d6838.js.map": "/static/js/main.361d6838.js.map"
   },
   "entrypoints": [
-    "static/css/main.a0945a9e.css",
-    "static/js/main.56f8eb9b.js"
+    "static/css/main.00d05e81.css",
+    "static/js/main.361d6838.js"
   ]
 }