fix: align homepage feature checklist

Wrapped feature rows were centered independently, which shifted the lower-right item away from the column above it. The Chinese homepage now uses a shared two-column grid and collapses to one aligned column on narrow screens.

Release note: 官网首页特性列表现在按列对齐，桌面与移动端布局更整齐。

sites/index.html

@@ -133,7 +133,7 @@
               <a class="button button--primary" href="#download">立即下载</a>
               <a class="button button--secondary" href="#features">了解 Agent Runtime</a>
             </div>
-            <ul class="hero-facts" aria-label="产品特性概览">
+            <ul class="hero-facts hero-facts--aligned" aria-label="产品特性概览">
               <li>
                 <svg viewBox="0 0 20 20" aria-hidden="true"><path d="m5 10 3 3 7-7" /></svg>
                 3 大桌面系统，x64 / arm64

sites/styles.css

@@ -586,6 +586,11 @@ p {
   list-style: none;
 }
 
+.hero-facts--aligned {
+  display: grid;
+  grid-template-columns: repeat(2, minmax(0, max-content));
+}
+
 .hero-facts li {
   display: flex;
   align-items: center;
@@ -1839,6 +1844,10 @@ p {
     gap: var(--space-2);
   }
 
+  .hero-facts--aligned {
+    grid-template-columns: minmax(0, max-content);
+  }
+
   .product-stage {
     min-height: 365px;
     margin-top: var(--space-4);