feat: Add originalStartTime to event DTOs and service to correctly identify and manage event exceptions in the UI.

server/src/calendar/calendar.service.ts

@@ -62,10 +62,10 @@ type BookingWithUserDto = {
   id: number;
 };
 
-// The final shape of a calendar event occurrence
 export type CalendarEventDto = Omit<Event, 'bookings'> & {
   isModified?: boolean;
   isCancelled?: boolean;
+  originalStartTime: Date;
   eventBookings: BookingWithUserDto[];
 };
 
@@ -146,6 +146,7 @@ export class CalendarService {
       const key = `${event.id}-${event.startTime.getTime()}`;
       return {
         ...event,
+        originalStartTime: event.startTime,
         eventBookings: bookingMap.get(key) || [],
       };
     });
@@ -197,6 +198,7 @@ export class CalendarService {
               exception.newEndTime ||
               new Date(occurrenceDate.getTime() + duration),
             isModified: true,
+            originalStartTime: occurrenceDate,
             eventBookings: bookingMap.get(key) || [],
             isCancelled: !!exception.isCancelled,
           });
@@ -206,6 +208,7 @@ export class CalendarService {
           recurringOccurrences.push({
             ...event,
             startTime: occurrenceDate,
+            originalStartTime: occurrenceDate,
             endTime: new Date(occurrenceDate.getTime() + duration),
             eventBookings: bookingMap.get(key) || [],
           });