replaced generic "Event" label with substitution or lesson text

lib/view/pages/timetable/data/lesson_type_label.dart

@@ -1,4 +1,5 @@
 import '../../../../api/marianumconnect/queries/timetable_get_week/timetable_get_week_response.dart';
+import 'lesson_labels.dart';
 
 /// Derives a human-readable title from the Marianum-Connect `lessonType` for
 /// lessons that have no subject of their own (Aufsicht, Sprechstunde, …).
@@ -10,10 +11,20 @@ class LessonTypeLabel {
 
   static String forEntry(McTimetableEntry lesson) {
     final base = baseLabel(lesson.lessonType);
+    if (base == fallback) {
+      final text = entryText(lesson);
+      if (text != null) return text;
+    }
     final room = (lesson.rooms.firstOrNull ?? '').trim();
     return room.isEmpty ? base : '$room $base';
   }
 
+  /// Webuntis-Freitext eines fachlosen Eintrags („Klassenfahrt 8a“), der
+  /// aussagekräftiger ist als das generische „Event“.
+  static String? entryText(McTimetableEntry lesson) =>
+      collapseWhitespace(lesson.substitutionText) ??
+      collapseWhitespace(lesson.lessonText);
+
   /// Returns just the type wording without the room — useful when the caller
   /// renders the room separately (e.g. as a subtitle line).
   static String baseLabel(String lessonType) {

lib/view/pages/timetable/details/lesson_sheet.dart

@@ -10,6 +10,7 @@ import '../../../../state/app/modules/timetable/bloc/timetable_bloc.dart';
 import '../../../../state/app/modules/timetable/bloc/timetable_state.dart';
 import '../../../../widget/debug/debug_tile.dart';
 import '../../../../widget/details_bottom_sheet.dart';
+import '../data/lesson_labels.dart';
 import '../data/lesson_type_label.dart';
 import '../subject_colors/subject_color_picker.dart';
 
@@ -226,10 +227,13 @@ class LessonSheet {
   }
 
   static List<Widget> _optionalTextTiles(McTimetableEntry lesson) {
+    final sameText =
+        collapseWhitespace(lesson.lessonText) ==
+        collapseWhitespace(lesson.substitutionText);
     return <Widget?>[
       _textTile(Icons.info_outline, 'Info', lesson.infoText),
       _textTile(Icons.swap_horiz, 'Vertretungstext', lesson.substitutionText),
-      _textTile(Icons.subject, 'Stundentext', lesson.lessonText),
+      if (!sameText) _textTile(Icons.subject, 'Stundentext', lesson.lessonText),
       _textTile(
         Icons.category_outlined,
         'Stundentyp',