refactor: Split EventFormFields.tsx into smaller modules

- Extract helper functions to utils/dateTimeHelpers.ts and utils/dateTimeFormatters.ts
- Extract validation logic to utils/formValidation.ts
- Extract FieldWithLabel component to components/FieldWithLabel.tsx
- Extract DateTimeFields component to components/DateTimeFields.tsx
- Extract all-day toggle logic to hooks/useAllDayToggle.ts
- Update imports in EventModal.tsx, EventUpdateModal.tsx, EventDisplay.tsx, eventHandlers.ts
- Maintain all existing functionality without breaking changes

src/features/Events/EventDisplay.tsx

@@ -46,7 +46,7 @@ import {
 import { Calendars } from "../Calendars/CalendarTypes";
 import { userAttendee } from "../User/userDataTypes";
 import { getEvent } from "./EventApi";
-import { formatLocalDateTime } from "../../components/Event/EventFormFields";
+import { formatLocalDateTime } from "../../components/Event/utils/dateTimeFormatters";
 import { CalendarEvent, RepetitionObject } from "./EventsTypes";
 
 export default function EventDisplayModal({

src/features/Events/EventModal.tsx

@@ -24,10 +24,11 @@ import {
 } from "../../components/Calendar/TimezoneSelector";
 import { getCalendarRange } from "../../utils/dateUtils";
 import { updateTempCalendar } from "../../components/Calendar/utils/calendarUtils";
-import EventFormFields, {
+import EventFormFields from "../../components/Event/EventFormFields";
+import {
   formatLocalDateTime,
   formatDateTimeInTimezone,
-} from "../../components/Event/EventFormFields";
+} from "../../components/Event/utils/dateTimeFormatters";
 
 function EventPopover({
   anchorEl,

src/features/Events/EventUpdateModal.tsx

@@ -17,9 +17,8 @@ import { userAttendee } from "../User/userDataTypes";
 import { CalendarEvent, RepetitionObject } from "./EventsTypes";
 import { TIMEZONES } from "../../utils/timezone-data";
 import { addVideoConferenceToDescription } from "../../utils/videoConferenceUtils";
-import EventFormFields, {
-  formatDateTimeInTimezone,
-} from "../../components/Event/EventFormFields";
+import EventFormFields from "../../components/Event/EventFormFields";
+import { formatDateTimeInTimezone } from "../../components/Event/utils/dateTimeFormatters";
 import { getEvent, deleteEvent, putEvent } from "./EventApi";
 import { refreshCalendars } from "../../components/Event/utils/eventUtils";
 import { getCalendarRange } from "../../utils/dateUtils";