event delete on a recurring event previously deleted the entire .ics file,
killing the whole series. Now requires --date (adds EXDATE) or --all (deletes
series) for recurring events, refusing to act without either flag.
Add --rrule flag to send with DTSTART/BYDAY validation (RFC 5545).
Add event list (via khal) and event delete (safe single-event removal).
Document safety rules from 2026-03-25 incident: always dry-run recurring
events, never rm .ics files, space out SMTP sends.
Remove three redundant email flows since all devices sync via CalDAV:
- Auto-adding mail@luyx.org as attendee on outgoing invites
- Forwarding invites to mail@luyx.org on accept/tentative
- Emailing todos to mail@luyx.org on todo add
