feat(git): add switch branch functionality with error handling

[avrum]

Adding branch easy checkout option

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[maxtara]

Would love a copy button, make it consistent with DIRECTORY.
That will sort of conflict with the "worktree" text when running on a worktree though The worktree text is a little annoying as it means you can see so little of the branch name (rest is hidden) - maybe it could be an icon too?