Merge a branch from the worktree.
If you're currently working on a worktree, assume that's the one I'm referring to.

Start by committing any staged and unstaged changes. I may have made changes to the worktree manually.
Then merge back the new main branch, since I may have made changes to it.

# Language specific:

## Rust

Ensure cargo check is happy.
Ensure clippy is happy. clean up any new warnings.

## Typescript

Ensure tsc is happy.

# Finally

Use `gh pr merge --squash` to merge the PR server-side (so GitHub marks it as "merged", not "closed").
Then delete the local worktree and branch.