修改状态监控页面总览和路口左侧菜单默认只显示到区，默认不展开子区及路口点

src/components/ui/MenuItem.vue

@@ -35,12 +35,13 @@
     </div>
 
     <div class="menu-children" v-show="isOpen" v-if="hasChildren">
-      <MenuItem 
-        v-for="child in node.children" 
-        :key="child.id" 
-        :node="child" 
+      <MenuItem
+        v-for="child in node.children"
+        :key="child.id"
+        :node="child"
         :level="level + 1"
-        :theme="theme" 
+        :theme="theme"
+        :defaultExpandLevel="defaultExpandLevel"
         @node-click="passEventUp"
         @folder-click="passFolderClickUp"
       >
@@ -67,12 +68,17 @@ export default {
     // 可选值：'tech' (科技渐变) | 'dark' (极简暗色)
     theme: {
       type: String,
-      default: 'tech' 
+      default: 'tech'
+    },
+    // 默认展开到第几层（不含该层），例如 2 表示 level 0、1 展开，level 2 起折叠
+    defaultExpandLevel: {
+      type: Number,
+      default: 2
     }
   },
   data() {
     return {
-      isOpen: true 
+      isOpen: this.level < this.defaultExpandLevel
     };
   },
   computed: {