fix(layout): 顶部导航下拉子菜单图标与文字间距

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/ty-header.vue

@@ -17,6 +17,7 @@
         mode="horizontal"
         :ellipsis="false"
         :default-active="activeIndex"
+        popper-class="ty-header-menu-popper"
         @select="onNavSelect"
       >
         <template v-for="item in menus" :key="item.code">
@@ -232,4 +233,9 @@ function onUserCommand(command: string): void {
     }
   }
 }
+
+/* 横向导航下拉子菜单（popper 逃逸到 body）里的图标与文字间距 */
+:global(.ty-header-menu-popper .icon) {
+  @apply mr-1;
+}
 </style>