Drop 10 min / 2 h / 2 days, add 1 week, and use full-word "… vorher" /
"… before" labels so the choices match the web client.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Per-event reminders (multiple, local calendars only) in the editor, prefilled
from a new "default reminder" setting that applies to all events otherwise.
CalEvent gains `reminders`; AppSettings/SettingsSync sync default_reminder_minutes
(always group). New NotificationScheduler requests permission and schedules the
soonest ≤60 upcoming reminders via UNUserNotificationCenter, rescheduling on
load/sync/edit and when the default changes (skipped in group overlay).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
