refactored data providers with centralized cache resolution, unified UI using custom dialogs and bottom sheets, and enhanced network error handling for Dio and TLS errors

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

@@ -429,8 +429,7 @@ class _OverflowTile extends StatelessWidget {
       padding: const EdgeInsets.all(1),
       child: Stack(
         children: [
-          // Card peeking out at the bottom — visual hint that more cards lie
-          // underneath the visible one.
+          // Stacked-cards effect: a darker layer peeks out below the front card.
           Positioned(
             top: 4,
             left: 2,
@@ -443,7 +442,6 @@ class _OverflowTile extends StatelessWidget {
               ),
             ),
           ),
-          // Front card with the "+N" indicator.
           Positioned(
             top: 0,
             left: 0,