List venue booking conflicts

Option and confirmed (non-archived) events that would collide with a booking of this venue over the date window. An event occupies the spaces it books, or the whole venue when it books none (or when the venue is only rented whole); two events collide when their dates overlap and so do their footprints. Pass space_ids to check a booking of some spaces only; without it the check is for the whole venue, so every event of the venue in the window is returned. venueId may be a space: the check then runs on its venue for that space. Dates are calendar days of the venue's own time zone. A combined space (e.g. Salon AB = Salon A + Salon B, see combined_space_ids) takes its parts: it collides with each part and with any combination sharing one, while two parts do not collide with each other. A space's set-up / tear-down minutes widen each of its slots, and a slot running past midnight (22:00 → 02:00) still holds the next morning. The response also lists the venue's closures on those days (and those of the requested spaces) and the days it does not open (outside_hours), with its enforcement mode. Role permission: none (any member).