Invite emails (a text/calendar part or an .ics attachment) now show the
event in place of the body: a date tile, the time in your zone, who's
invited and their answers, the call link, place and description, with
the email itself behind "⋯". Invitations get Accept / Maybe / Decline,
which send an RFC 5546 REPLY to the organizer at once (as a calendar
alternative and as reply.ics) and keep the answer with the message;
replies and cancellations get a banner.

The iCalendar reader is our own: it uses the time zones the invite
defines (Outlook, Apple) or UTC (Google), and leaves unknown zones
floating. On Microsoft 365, meeting messages are read from their MIME,
and replies go out through sendMail as MIME. Mail stored before this
change isn't re-read.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>