Patch release: you can permanently delete a session with /delete (or from the resume picker).
Changelog
[new]/delete removes the current session’s history (with confirmation) and returns you to the welcome screen. To delete a session you are not in, open /resume, press d, then y.
[changed] Background monitors are steered to stay quiet: each stdout line wakes the main agent, so watch scripts should emit only terminal status (DONE / FAILED / CANCELLED), not progress noise.