fix(vr page): optimize navigation bar title setting logic

add optional chaining to safely access res.data.title,
only set navigation bar title when title exists, fallback to default removed

pages_tool/vr/index.vue

@@ -12,15 +12,15 @@ export default {
 		};
 	},
 	onLoad(option) {
-		// 确保导航栏标题显示
-		
 		this.$api.sendRequest({
 			url: '/api/config/defaultvr',
 			success: res => {
 				if (res.code == 0) {
-					uni.setNavigationBarTitle({
-						title: res.data.title || '工厂展示'
-					});
+					if (res.data?.title) {
+						uni.setNavigationBarTitle({
+							title: res.data.title
+						});
+					}
 					this.src = res.data.url
 				}
 			},