added teacher-focused lesson sheet with direct class and teacher timetable links

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

@@ -73,5 +73,6 @@ class LessonMerger {
     substitutionText: source.substitutionText,
     lessonText: source.lessonText,
     infoText: source.infoText,
+    classIds: source.classIds,
   );
 }

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

@@ -240,12 +240,14 @@ class TimetableAppointmentFactory {
   String _locationLabel(McTimetableEntry lesson) {
     final roomName =
         collapseWhitespace(lesson.rooms.firstOrNull) ?? 'Unbekannt';
-    // Klassenlose Einträge (Aufsichten etc.) fallen auf den Lehrer zurück.
-    final secondLine =
-        (showClassInsteadOfTeacher ? lesson.classLabel : null) ??
-        _teacherLabel(lesson.teachers.firstOrNull) ??
-        'Unbekannt';
-    return '$roomName\n$secondLine';
+    if (showClassInsteadOfTeacher) {
+      // Klassenlose Einträge (Aufsichten etc.) zeigen nur den Raum — die
+      // Lehrkraft wäre hier die Plan-Inhaberin selbst.
+      final classLabel = lesson.classLabel;
+      return classLabel == null ? roomName : '$roomName\n$classLabel';
+    }
+    final teacher = _teacherLabel(lesson.teachers.firstOrNull) ?? 'Unbekannt';
+    return '$roomName\n$teacher';
   }
 
   /// Backend serves teachers with their full display name ("Stefan Müller"),