implemented DST-safe date arithmetic with new addDays and subtractDays extensions, updated timetable state to reset view and scroll boundaries on initialization to prevent stale views, added hard caps to calendar navigation, and updated version to 1.0.3+52

lib/view/pages/timetable/widgets/calendar/day_header.dart

@@ -19,7 +19,7 @@ class _DayHeaderStrip extends StatelessWidget {
       for (var d = 0; d < 5; d++)
         Expanded(
           child: _DayHeaderCell(
-            date: weekStart.add(Duration(days: d)),
+            date: weekStart.addDays(d),
             today: today,
           ),
         ),

lib/view/pages/timetable/widgets/calendar/week_grid.dart

@@ -38,7 +38,7 @@ class _WeekGrid extends StatelessWidget {
         for (var d = 0; d < 5; d++)
           Expanded(
             child: _DayColumn(
-              date: weekStart.add(Duration(days: d)),
+              date: weekStart.addDays(d),
               schedule: schedule,
               appointments: partitioned.inside[d],
               timeRegions: timeRegions,