I have CI set up so that I can just let that handle builds and exclusive locks for me, but there are particular limitations (network connectivity is mandatory). I did this because I wanted to avoid something like you built, which theoretically can't scale as well as a dev box (much easier to extend deploy environments versus my local machine). I can see that you are working within resource constraints though which is admirable :)

A decent idea, however it seems to me a good chunk of it is because of git limitations. Have you looked jj?

I'm having a much better time with jj and a workspace per subagent than I was with git and worktrees.

It's still useful to have the CI gating on updating the master branch pointer, but you largely stop working with branches once you switch to jj.