bug: vp install can finish work but hang without exiting after vp up -r --latest

### Reproduction

This seems to happen frequently after updating dependencies:

1. Run `vp up -r --latest`
2. Run `vp install`
3. Run `vp install` again if the lockfile/catalog state needs another pass after the update
4. The second `vp install` does all the work and appears finished, but the process does not exit

### Actual behavior

`vp install` appears done, but hangs instead of exiting cleanly.

### Expected behavior

Once install work is complete, `vp install` should exit normally.

### Notes

- This reproduces for me almost every time I update deps
- I just hit it on Codiff
- It used to happen on fate.technology as well

CC @fengmk2

运行 `vp up -r --latest` 复现挂起，然后按照描述重复执行 `vp install`，并确认第二个命令完成工作但没有退出。从 `vp install` 命令的入口点开始，跟踪安装完成后的进程；在报告的依赖项更新场景中，命令正常退出即表示完成。

由索引模型根据 Issue 内容生成。