feat(web): sales/index.html 产品介绍分类挂载减重套餐卡片 (4→5篇)

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-openagent)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

web/sales/index.html

@@ -609,9 +609,18 @@
 
   <!-- ===== 产品介绍 ===== -->
   <div class="category">
-    <h2 class="category-title" id="products">📦 产品介绍 <span class="count">4篇</span></h2>
+    <h2 class="category-title" id="products">📦 产品介绍 <span class="count">5篇</span></h2>
     <div class="card-grid">
 
+      <a href="../product-intro/weight-loss-package.html" class="card indigo">
+        <div class="card-header">
+          <h3>家庭科学减重套餐 · 产品介绍</h3>
+          <span class="tag">减重套餐</span>
+        </div>
+        <p>先检测后干预：肠道菌群基因检测8大维度定位肥胖根源，报告驱动定制饮食、营养品、运动、睡眠四维方案，每日任务执行与提醒打卡。支持双人/三人家庭套餐。</p>
+        <div class="meta"><span class="sales-product">→ 科学减重</span><span>检测驱动 · 四维方案 · 全家同行</span></div>
+      </a>
+
       <a href="../product-intro/gut-testing.html" class="card indigo">
         <div class="card-header">
           <h3>肠道菌群基因检测 · 产品介绍</h3>