带鱼屏客户端内容锁 1800 居中，普通屏全宽；内嵌与独立打开一致。

Co-authored-by: Cursor <cursoragent@cursor.com>

lib/instance/templates/index.html

@@ -18,7 +18,7 @@
     <link rel="apple-touch-icon" href="/static/icons/apple-touch-icon.png">
     <link rel="manifest" href="/static/icons/manifest.webmanifest">
     <title>{{ pwa_app_name }}</title>
-    <link rel="stylesheet" href="/static/instance_page.css?v=24">
+    <link rel="stylesheet" href="/static/instance_page.css?v=25">
     <link rel="stylesheet" href="/static/instance_theme.css?v=126">
 
 </head>