feat(events): reliable holiday skipping for recurrences + UI badge; clean logs

Backend: generate EventException on create/update when skip_holidays or recurrence changes; emit RecurrenceException (EXDATE) with exact occurrence start time (UTC)
API: return master events with RecurrenceRule + RecurrenceException
Frontend: map RecurrenceException → recurrenceException; ensure SkipHolidays instances never render on holidays; place TentTree icon (black) next to main event icon via template
Docs: update README and Copilot instructions for recurrence/holiday behavior
Cleanup: remove dataSource and debug console logs

dashboard/src/apiEvents.ts

@@ -8,10 +8,18 @@ export interface Event {
   extendedProps: Record<string, unknown>;
 }
 
-export async function fetchEvents(groupId: string, showInactive = false) {
-  const res = await fetch(
-    `/api/events?group_id=${encodeURIComponent(groupId)}&show_inactive=${showInactive ? '1' : '0'}`
-  );
+export async function fetchEvents(
+  groupId: string,
+  showInactive = false,
+  options?: { start?: Date; end?: Date; expand?: boolean }
+) {
+  const params = new URLSearchParams();
+  params.set('group_id', groupId);
+  params.set('show_inactive', showInactive ? '1' : '0');
+  if (options?.start) params.set('start', options.start.toISOString());
+  if (options?.end) params.set('end', options.end.toISOString());
+  if (options?.expand) params.set('expand', options.expand ? '1' : '0');
+  const res = await fetch(`/api/events?${params.toString()}`);
   const data = await res.json();
   if (!res.ok || data.error) throw new Error(data.error || 'Fehler beim Laden der Termine');
   return data;