fix: 优化分站 API Key 页面显示细节

- 移除空状态冗余创建按钮，改为提示点击上方卡片
- 移除 My API Keys 标题栏多余的新建按钮
- ConfigExporter 无 key 时提示改为"请先创建 API Key"
- 修复 KeyGroupCard 推荐/折扣标签颜色适配所有主题

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

dist/index.html

@@ -7,8 +7,8 @@
     <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin />
     <link href="https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&family=Noto+Sans+SC:wght@300;400;500;600;700&family=JetBrains+Mono:wght@400;500&display=swap" rel="stylesheet" />
     <title>AI Platform</title>
-    <script type="module" crossorigin src="/assets/index-CUSQSzW8.js"></script>
-    <link rel="stylesheet" crossorigin href="/assets/index-DMSxfHZb.css">
+    <script type="module" crossorigin src="/assets/index-BxETo_Fm.js"></script>
+    <link rel="stylesheet" crossorigin href="/assets/index-B9svmztF.css">
   </head>
   <body class="antialiased">
     <script>