refactored broad range of the application, split files, modularized calendar and file views, centralized bottom sheets and clipboard handling, and implemented unit test coverage

lib/view/pages/timetable/details/custom_event_sheet.dart

@@ -1,21 +1,19 @@
 import 'package:flutter/material.dart';
-import 'package:jiffy/jiffy.dart';
 import 'package:rrule/rrule.dart';
 
 import '../../../../api/mhsl/custom_timetable_event/custom_timetable_event.dart';
+import '../../../../extensions/date_time.dart';
 import '../../../../widget/centered_leading.dart';
 import '../../../../widget/debug/debug_tile.dart';
+import '../../../../widget/details_bottom_sheet.dart';
 import '../custom_events/custom_event_edit_dialog.dart';
-import 'bottom_sheet.dart';
 import 'delete_custom_event.dart';
 
 class CustomEventSheet {
   static void show(BuildContext context, CustomTimetableEvent event) {
-    final timeRange =
-        '${Jiffy.parseFromDateTime(event.startDate).format(pattern: 'HH:mm')} - '
-        '${Jiffy.parseFromDateTime(event.endDate).format(pattern: 'HH:mm')}';
+    final timeRange = event.startDate.timeRangeTo(event.endDate);
 
-    showAppointmentBottomSheet(
+    showDetailsBottomSheet(
       context,
       header: ListTile(
         leading: const Icon(Icons.event_outlined, size: 32),