implemented custom subject colors for the timetable and unified the color palette system

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

@@ -10,13 +10,20 @@ class AppointmentDetailsDispatcher {
   static void show(
     BuildContext context,
     TimetableState? state,
-    Appointment appointment,
-  ) {
+    Appointment appointment, {
+    bool canEditSubjectColor = false,
+  }) {
     final id = appointment.id;
     if (id is! ArbitraryAppointment) return;
 
     id.when(
-      lesson: (entry) => LessonSheet.show(context, state, appointment, entry),
+      lesson: (entry) => LessonSheet.show(
+        context,
+        state,
+        appointment,
+        entry,
+        canEditSubjectColor: canEditSubjectColor,
+      ),
       custom: (event) => CustomEventSheet.show(context, event),
     );
   }

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

@@ -1,18 +1,22 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:rrule/rrule.dart';
 
 import '../../../../api/mhsl/custom_timetable_event/custom_timetable_event.dart';
 import '../../../../extensions/date_time.dart';
+import '../../../../state/app/modules/timetable/bloc/timetable_bloc.dart';
 import '../../../../widget/centered_leading.dart';
 import '../../../../widget/debug/debug_tile.dart';
 import '../../../../widget/details_bottom_sheet.dart';
 import '../custom_events/custom_event_edit_dialog.dart';
 import '../data/rrule_with_exceptions.dart';
+import '../subject_colors/subject_color_picker.dart';
 import 'delete_custom_event.dart';
 
 class CustomEventSheet {
   static void show(BuildContext context, CustomTimetableEvent event) {
     final timeRange = event.startDate.timeRangeTo(event.endDate);
+    final bloc = context.read<TimetableBloc>();
 
     showDetailsBottomSheet(
       context,
@@ -23,6 +27,12 @@ class CustomEventSheet {
           style: const TextStyle(fontWeight: FontWeight.bold),
         ),
         subtitle: Text(timeRange),
+        trailing: TimetableColorHeaderButton(
+          initialColorName: event.color,
+          pickerTitle: 'Farbe wählen',
+          onSelected: (option) =>
+              bloc.updateCustomEvent(event.id, _withColor(event, option.name)),
+        ),
       ),
       children: (sheetCtx) => [
         Padding(
@@ -104,4 +114,18 @@ class CustomEventSheet {
       ],
     );
   }
+
+  static CustomTimetableEvent _withColor(CustomTimetableEvent e, String color) =>
+      CustomTimetableEvent(
+        id: e.id,
+        title: e.title,
+        description: e.description,
+        startDate: e.startDate,
+        endDate: e.endDate,
+        color: color,
+        rrule: e.rrule,
+        skipHolidays: e.skipHolidays,
+        createdAt: e.createdAt,
+        updatedAt: DateTime.now(),
+      );
 }

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

@@ -1,31 +1,39 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:syncfusion_flutter_calendar/calendar.dart';
 
 import '../../../../api/marianumconnect/queries/timetable_get_week/timetable_get_week_response.dart';
 import '../../../../extensions/date_time.dart';
 import '../../../../extensions/text.dart';
 import '../../../../routing/app_routes.dart';
+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_type_label.dart';
+import '../subject_colors/subject_color_picker.dart';
 
 class LessonSheet {
   static void show(
     BuildContext context,
     TimetableState? state,
     Appointment appointment,
-    McTimetableEntry lesson,
-  ) {
+    McTimetableEntry lesson, {
+    bool canEditSubjectColor = false,
+  }) {
     if (state == null) return;
 
+    // In Fremdansichten würde der Farb-Button die eigene, globale Fach-Farbe
+    // ändern, ohne dass sich der fremde Plan aktualisiert — daher nur im
+    // eigenen Plan anbieten. Die Einfärbung (eigene Farben) bleibt.
+    final bloc = context.read<TimetableBloc>();
     final subjectShort = lesson.subjects.firstOrNull;
-    final headerLong = subjectShort == null
+    final subjectEntry = subjectShort == null
         ? null
         : state.subjects?.result
               .where((s) => s.shortName == subjectShort)
-              .firstOrNull
-              ?.longName;
+              .firstOrNull;
+    final headerLong = subjectEntry?.longName;
     // Bei Stunden ohne Fach (Pausenaufsicht etc.) den Lesson-Type-Titel
     // einsetzen — sonst stünde im Header nur ein generisches "?".
     final headerTitle = subjectShort != null
@@ -50,6 +58,18 @@ class LessonSheet {
           headerLongName.isNotEmpty ? '$timeRange\n$headerLongName' : timeRange,
         ),
         isThreeLine: headerLongName.isNotEmpty,
+        trailing: canEditSubjectColor && subjectShort != null
+            ? TimetableColorHeaderButton(
+                initialColorName: subjectEntry?.color,
+                pickerTitle: (headerLong != null && headerLong.isNotEmpty)
+                    ? 'Farbe: $headerLong'
+                    : 'Farbe: $subjectShort',
+                pickerSubtitle: 'Nur reguläre Stunden werden eingefärbt',
+                onSelected: (option) =>
+                    bloc.setSubjectColor(subjectShort, option.name),
+                onReset: () => bloc.clearSubjectColor(subjectShort),
+              )
+            : null,
       ),
       children: (_) => <Widget>[
         ListTile(