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

lib/api/webuntis/queries/get_subjects/get_subjects.dart

@@ -0,0 +1,14 @@
+import 'dart:convert';
+
+import '../../webuntis_api.dart';
+import 'get_subjects_response.dart';
+
+class GetSubjects extends WebuntisApi {
+  GetSubjects() : super('getSubjects', null);
+
+  @override
+  Future<GetSubjectsResponse> run() async {
+    final rawAnswer = await query(this);
+    return finalize(GetSubjectsResponse.fromJson(jsonDecode(rawAnswer) as Map<String, dynamic>));
+  }
+}