Remove a git worktree checkout, delete its branch, and close the herdr workspace or tmux window showing it. Resolves the target from a branch name, directory slug, absolute path, or the worktree you are standing in. Use whenever the user wants a worktree gone: "wt remove", "delete this worktree", "close and remove that herdr worktree workspace", "tear down the branch I spun out". This is the only worktree-removal skill; there is no herdr-specific variant.
