看着大佬的文章也实现了一版

在原 Demo 上还增加了：
1. 电梯上行按钮
2. 抵达目标楼层会稍微停留
3. 稍微丰富一点的交互和视觉效果

[电梯模拟器 Demo 仓库](https://github.com/KaygNas/learning-demo/tree/rxjs)
[在线预览](https://codepen.io/sangyaaak/full/PoJKKpR)（没什么，就是想秀一下😏）

Review the original Demo alongside the linked learning-demo repository branch and the CodePen preview to understand the elevator simulator changes. The issue has no requested change or acceptance criteria, so there is no defined completion condition for a newcomer.

Written by the indexing model from the issue text.