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/appointment_tile.dart

@@ -2,14 +2,11 @@ import 'package:flutter/material.dart';
 import 'package:syncfusion_flutter_calendar/calendar.dart';
 
 import '../data/arbitrary_appointment.dart';
+import '../data/calendar_layout.dart';
 import 'cross_painter.dart';
 
 class AppointmentTile extends StatelessWidget {
   static const _radius = BorderRadius.all(Radius.circular(7));
-  static const _titleFontSize = 15.0;
-  static const _titleMinFontSize = 11.0;
-  static const _bodyFontSize = 10.0;
-  static const _bodyLineHeight = 1.15;
 
   final Appointment appointment;
   final bool crossedOut;
@@ -42,8 +39,8 @@ class AppointmentTile extends StatelessWidget {
                 children: [
                   _AdaptiveTitle(
                     text: appointment.subject,
-                    fontSize: _titleFontSize,
-                    minFontSize: _titleMinFontSize,
+                    fontSize: kAppointmentTitleFontSize,
+                    minFontSize: kAppointmentTitleMinFontSize,
                     fontWeight: FontWeight.w500,
                   ),
                   if (isCustom) ...[
@@ -53,8 +50,8 @@ class AppointmentTile extends StatelessWidget {
                           padding: const EdgeInsets.only(top: 1),
                           child: _WrappingBody(
                             text: description,
-                            fontSize: _bodyFontSize,
-                            lineHeight: _bodyLineHeight,
+                            fontSize: kAppointmentBodyFontSize,
+                            lineHeight: kAppointmentBodyLineHeight,
                           ),
                         ),
                       ),
@@ -63,7 +60,7 @@ class AppointmentTile extends StatelessWidget {
                         .split('\n')
                         .where((p) => p.isNotEmpty)
                         .take(2))
-                      _ScaledLine(text: line, fontSize: _bodyFontSize),
+                      _ScaledLine(text: line, fontSize: kAppointmentBodyFontSize),
                   ],
                 ],
               ),