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/view/pages/timetable/timetable.dart

@@ -2,7 +2,6 @@ import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:syncfusion_flutter_calendar/calendar.dart';
 
-import '../../../extensions/date_time.dart';
 import '../../../routing/app_routes.dart';
 import '../../../state/app/infrastructure/loadable_state/view/loadable_state_consumer.dart';
 import '../../../state/app/modules/settings/bloc/settings_cubit.dart';
@@ -13,6 +12,7 @@ import 'custom_events/custom_event_edit_dialog.dart';
 import 'data/arbitrary_appointment.dart';
 import 'data/lesson_period_schedule.dart';
 import 'data/timetable_appointment_factory.dart';
+import 'data/webuntis_time.dart';
 import 'details/appointment_details_dispatcher.dart';
 import 'widgets/custom_workweek_calendar.dart';
 import 'widgets/special_regions_builder.dart';
@@ -147,18 +147,20 @@ class _TimetableState extends State<Timetable> {
       disabledColor: Theme.of(context).disabledColor,
     ).build();
 
+    // Scroll bounds follow the Webuntis school-year API: the calendar lets
+    // the user navigate every week the server has data for. A two-week
+    // fallback is used only while the school-year payload hasn't loaded yet
+    // (first launch / offline), so the calendar still mounts.
+    final (minDate, maxDate) = _scrollBounds(state);
+
     return CustomWorkWeekCalendar(
       key: _calendarKey,
       schedule: schedule,
       appointments: appointments,
       timeRegions: regions,
       initialDate: _initialDisplayDate(),
-      minDate: DateTime.now()
-          .subtract(const Duration(days: 14))
-          .nextWeekday(DateTime.sunday),
-      maxDate: DateTime.now()
-          .add(const Duration(days: 7))
-          .nextWeekday(DateTime.saturday),
+      minDate: minDate,
+      maxDate: maxDate,
       onAppointmentTap: (apt) =>
           AppointmentDetailsDispatcher.show(context, bloc, apt),
       onWeekChanged: (start, end) => bloc.changeWeek(start, end),
@@ -175,4 +177,43 @@ class _TimetableState extends State<Timetable> {
       barrierDismissible: false,
     );
   }
+
+  /// Returns the (minDate, maxDate) the user is allowed to scroll between.
+  /// Starts from the Webuntis school year (or a tight window when that
+  /// hasn't loaded yet) and tightens by anything the bloc has learned
+  /// from `-7004 no allowed date` errors during scroll — so the user
+  /// can't slide off into territory Webuntis would refuse anyway.
+  ///
+  /// minDate is snapped *forward* to the next Monday because the calendar's
+  /// internal `_mondayOf()` would otherwise pull a mid-week minDate back
+  /// into the just-rejected week. maxDate is passed through unsnapped —
+  /// `_mondayOf()` correctly walks back to the Monday of its own week,
+  /// which is the last fully-allowed week.
+  (DateTime, DateTime) _scrollBounds(TimetableState state) {
+    final year = state.schoolyear?.result;
+    final DateTime baseMin;
+    final DateTime baseMax;
+    if (year != null) {
+      baseMin = WebuntisTime.parse(year.startDate, 0);
+      baseMax = WebuntisTime.parse(year.endDate, 0);
+    } else {
+      final now = DateTime.now();
+      baseMin = now.subtract(const Duration(days: 14));
+      baseMax = now.add(const Duration(days: 7));
+    }
+    final effectiveMin = state.accessibleStartDate != null
+        ? (state.accessibleStartDate!.isAfter(baseMin)
+              ? state.accessibleStartDate!
+              : baseMin)
+        : baseMin;
+    final effectiveMax = state.accessibleEndDate != null
+        ? (state.accessibleEndDate!.isBefore(baseMax)
+              ? state.accessibleEndDate!
+              : baseMax)
+        : baseMax;
+    final daysToMonday =
+        (DateTime.monday - effectiveMin.weekday) % DateTime.daysPerWeek;
+    final mondayMin = effectiveMin.add(Duration(days: daysToMonday));
+    return (mondayMin, effectiveMax);
+  }
 }