optimized avatar and linkify performance, refined navigation to preserve popups, implemented read marker caching, and added file size limits for saving, minor timetable details changes

lib/view/pages/marianum_dates/widgets/event_list_tile.dart

@@ -102,6 +102,7 @@ class MarianumDateRow extends StatelessWidget {
                   initialDescription: event.description,
                   initialStart: event.start,
                   initialEnd: event.end,
+                  initialAllDay: event.isAllDay,
                 ),
                 barrierDismissible: false,
               ),