feat: 分站套餐页增加限时特惠标识

- 页面顶部添加限时特惠横幅，提示当前为特价
- 每个套餐卡片增加"特惠价"徽章
- 价格区域增加折扣百分比标签和涨价提示
- 中英文 i18n 键补全

Co-Authored-By: Claude Sonnet 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-EC_zKUeV.js"></script>
-    <link rel="stylesheet" crossorigin href="/assets/index-CUoml65w.css">
+    <script type="module" crossorigin src="/assets/index-DFuC01Yj.js"></script>
+    <link rel="stylesheet" crossorigin href="/assets/index-Bv-3sd-D.css">
   </head>
   <body class="bg-black text-white antialiased">
     <div id="root"></div>