Bare operations so that this work with jujutsu, etc.

[chmnchiang]

I'm using jujutsu so please provide commands that does not create any branch, checkout any branch, etc.
For comparison, graphite has --branch arg for essential commands so it can work with jujutsu.

I'll even question why it isn't designed like this. Like you only need
gh stack <branch1> <branch2>: Stack branch1 on top of branch2, or if branch2 is missing, it will be the first branch in the stack
gh submit <branch>: Push a tracked branch to github.