feat: integrate undergraduate school workflows and period twelve

mobile/lib/features/timetable/week_grid.dart

@@ -14,7 +14,9 @@ class WeekGrid extends StatelessWidget {
     required this.monday,
     required this.today,
     required this.settings,
-  });
+    this.periodCount = 11,
+  }) : assert(periodCount == 11 || periodCount == 12);
+  final int periodCount;
   final List<CourseOccurrence> events;
   final DateTime monday, today;
   final AppSettings settings;
@@ -111,7 +113,7 @@ class WeekGrid extends StatelessWidget {
           (period - 1) * rowHeight +
           (period > 4 ? gap : 0) +
           (period > 8 ? gap : 0);
-      final height = 11 * rowHeight + 2 * gap;
+      final height = periodCount * rowHeight + 2 * gap;
       return Row(
         crossAxisAlignment: CrossAxisAlignment.start,
         children: [
@@ -120,7 +122,7 @@ class WeekGrid extends StatelessWidget {
             height: header + height,
             child: Stack(
               children: [
-                for (final slot in lessonSlots)
+                for (final slot in lessonSlots.take(periodCount))
                   Positioned(
                     top: header + top(slot.period),
                     left: 0,
@@ -244,7 +246,7 @@ class WeekGrid extends StatelessWidget {
                             ),
                           ),
                         ),
-                      for (var p = 1; p <= 11; p++)
+                      for (var p = 1; p <= periodCount; p++)
                         Positioned(
                           left: 0,
                           right: 0,