feat(layout): 顶部导航 top 布局菜单也支持无限级

- top 布局横向菜单改用 ty-menu-node 递归渲染
- 统一 icon 间距样式（:deep(.icon) 替代 .menu-icon）

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

src/components/ty-header.vue

@@ -20,17 +20,9 @@
         @select="onNavSelect"
       >
         <template v-for="item in menus" :key="item.code">
-          <el-sub-menu v-if="layout === 'top' && item.children?.length" :index="item.code">
-            <template #title>
-              <icon type="iconify" :icon="item.icon ?? 'mdi:menu'" class="menu-icon" />
-              <span>{{ item.name }}</span>
-            </template>
-            <el-menu-item v-for="child in item.children" :key="child.code" :index="child.path ?? child.code">
-              {{ child.name }}
-            </el-menu-item>
-          </el-sub-menu>
+          <ty-menu-node v-if="layout === 'top'" :node="item" />
           <el-menu-item v-else :index="item.code">
-            <icon type="iconify" :icon="item.icon ?? 'mdi:menu'" class="menu-icon" />
+            <icon type="iconify" :icon="item.icon ?? 'mdi:menu'" />
             <span>{{ item.name }}</span>
           </el-menu-item>
         </template>
@@ -219,7 +211,7 @@ function onUserCommand(command: string): void {
       color: var(--el-color-primary);
     }
 
-    :deep(.menu-icon) {
+    :deep(.icon) {
       @apply mr-1 text-base;
     }
   }