v0.8.0

Added

• Booked times can be shown struck through instead of hidden. Off by default, and
  enabled per event type under Visibility. Requested in
  #14, tracked as
  #19.

  For a public-hours use case - an intro call, a clinic, a tutor - a visibly busy
  calendar communicates demand, and an empty-looking list reads as "nothing here". It
  stays off by default because the slots endpoint is public and unauthenticated, so
  turning it on makes a host's booked hours legible to anyone with the link. That is a
  fair trade when the hours are already public and a privacy regression when they are
  not, so it is never inherited by upgrading.

  Only starts a booking or calendar conflict removed are shown. Times outside the host's
  working hours are never rendered, and times withheld by the minimum-notice rule are
  never shown as taken - nobody booked those, and saying so would corrupt the signal the
  feature exists to send. Booked times cannot be selected on any surface, and agents
  using the MCP tools or the booking assistant continue to see only bookable times.

  GET /v1/event-types/{slug}/slots gains a taken array for opted-in event types,
  absent otherwise. Event types gain show_taken_slots (migration 00057).