claude refactorings, flutter best practices, platform dependent changes, general cleanup

lib/state/app/modules/marianum_message/data_provider/marianum_message_get_messages.dart

@@ -0,0 +1,12 @@
+import 'package:dio/dio.dart';
+
+import '../../../basis/dataloader/mhsl_data_loader.dart';
+import '../../../infrastructure/data_loader/data_loader.dart';
+import '../bloc/marianum_message_state.dart';
+
+class MarianumMessageGetMessages extends MhslDataLoader<MarianumMessageList> {
+  @override
+  Future<Response<String>> fetch() async => dio.get('/message/messages.json');
+  @override
+  MarianumMessageList assemble(DataLoaderResult data) => MarianumMessageList.fromJson(data.asMap());
+}