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

[crusty-voidzero]

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