Worktree removal on exit now runs after the session ends

What

A worktree is a separate working copy of your git repository that a Claude Code session can work in. When you leave a worktree session you can remove it, and a clean worktree can be removed automatically. That removal now runs during Claude Code's shutdown instead of inside the exit dialog.

• Choosing 'Remove worktree', or the automatic removal of a clean worktree, no longer holds up the dialog for worktrees not created by a hook. The removal is handed off as a removeWorktree step that runs after the session ends. Before, the dialog waited for the removal and then showed the result.
• Worktrees created by a hook are still removed right away, inside the dialog.
• During shutdown, removeWorktreeAtExit prints "Removing worktree…" and runs with a time budget of at least 5 seconds.
• Pressing Ctrl+C or receiving a stop or hang-up signal (SIGINT, SIGTERM, SIGHUP) interrupts the removal, and a message warns that the folder may be partly deleted.
• When a tmux session is being closed and TMUX and CLAUDE_CODE_TMUX_SESSION match, the removal ignores the hang-up signal.
• If the session had switched away from that worktree, removal is refused with "Worktree not removed: this session had switched away from it before Claude Code exited".
• If a shutdown is already under way and a second request asks to remove a different worktree, a warning is logged that the worktree was kept. Before, this was silently dropped.
• The hint for resuming the session can now leave out the worktree once it has been removed (resumeHintOmitsWorktree).

Why

Exiting is quicker, but the result of the removal now appears after the dialog closes. If a worktree is left behind, the new messages say why, and an interrupted removal can leave a partly deleted folder to clean up.