Moving and resizing events

The bookings calendar inside <CalendarEditing>: drag an event to move it or its edge to resize it (a long-press on touch), or grab it from the keyboard (Space, the arrow keys, Enter). Open time, confirmed bookings and timed bookings are rules, and rejected drops say why; a fake API saves each change after a moment, slowly, or rejects or fails it, so pending changes, saves and reverts can be seen and heard. Sunday 25 October holds the hour that happens twice.