Manage local Git worktrees with the `wt` CLI, in herdr or tmux. Use whenever the user asks to create, open, remove, list, switch, or clean up worktrees, branches, herdr worktree workspaces, or tmux windows tied to worktrees: "wt new", "spin this out into a worktree", "open a herdr workspace for this branch", "close the finished worktrees", "clean up merged PR tabs". There is no separate herdr variant: `wt` detects the multiplexer itself, so route herdr-flavoured worktree requests here too.
