m's call 2026-05-19: opening /events with type=appointment was
defaulting status='all' which surfaces every past appointment in
the corpus. The default should hide past events; 'Alle (auch
vergangene)' is opt-in for the one user who actually wants the
historical view.
Replaces the default with the existing DeadlineFilterUpcoming bucket
(already implemented backend-side at internal/services/deadline_service.go:132
as 'today + future'). New status option 'upcoming' at the top of the
appointment list; existing 'all' moves to the bottom with a clearer
label that calls out 'incl. past'.
Deadlines unaffected — they still default to 'pending'.
i18n keys added in both DE + EN slots (events.filter.status.upcoming
'Ab heute' / 'From today'; .all reframed as 'Alle (auch vergangene)'
/ 'All (incl. past)').