implemented current schoolyear API and dynamic timetable scroll boundaries, added handling for out-of-range errors to narrow accessible dates, optimized holiday region rendering by collapsing overlaps, and refined holiday tile UI

lib/state/app/modules/timetable/bloc/timetable_state.dart

@@ -1,6 +1,7 @@
 import 'package:freezed_annotation/freezed_annotation.dart';
 
 import '../../../../../api/mhsl/custom_timetable_event/get/get_custom_timetable_event_response.dart';
+import '../../../../../api/webuntis/queries/get_current_schoolyear/get_current_schoolyear_response.dart';
 import '../../../../../api/webuntis/queries/get_holidays/get_holidays_response.dart';
 import '../../../../../api/webuntis/queries/get_rooms/get_rooms_response.dart';
 import '../../../../../api/webuntis/queries/get_subjects/get_subjects_response.dart';
@@ -20,11 +21,18 @@ abstract class TimetableState with _$TimetableState {
     GetRoomsResponse? rooms,
     GetSubjectsResponse? subjects,
     GetHolidaysResponse? schoolHolidays,
+    GetCurrentSchoolyearResponse? schoolyear,
     GetTimegridUnitsResponse? timegrid,
     GetCustomTimetableEventResponse? customEvents,
     required DateTime startDate,
     required DateTime endDate,
     @Default(0) int dataVersion,
+    // Boundaries learned from `-7004 no allowed date` errors during scroll.
+    // Inclusive: weeks whose start is on/before `accessibleEndDate` and
+    // whose end is on/after `accessibleStartDate` are within the user's
+    // permitted range. Null = no upper / lower bound discovered yet.
+    DateTime? accessibleStartDate,
+    DateTime? accessibleEndDate,
   }) = _TimetableState;
 
   factory TimetableState.fromJson(Map<String, Object?> json) =>