It's not anywhere near making PR ready (and never will be) but here is the branch [1]. I make no promises on it's functionality, and I only periodically rebase Herdr's latest over it. I have been using the jj change for awhile though with no issues. So YMMV.

You can also see the combined output of all my changes at [2], which Jujutsu makes so damn easy via megamerges.

1: https://github.com/giodamelio/herdr/tree/jj-workspace-migrat...

2: https://github.com/giodamelio/herdr/tree/combined-branch