added guardian login with views for their assigned childs

lib/api/marianumconnect/queries/get_capabilities/guardian_child.dart

@@ -0,0 +1,23 @@
+import 'package:freezed_annotation/freezed_annotation.dart';
+
+part 'guardian_child.freezed.dart';
+part 'guardian_child.g.dart';
+
+/// A student linked to the signed-in guardian. [id] is an opaque server id,
+/// not a WebUntis id.
+@freezed
+abstract class GuardianChild with _$GuardianChild {
+  const GuardianChild._();
+
+  const factory GuardianChild({
+    required String id,
+    required String firstName,
+    required String lastName,
+    @Default('') String className,
+  }) = _GuardianChild;
+
+  factory GuardianChild.fromJson(Map<String, Object?> json) =>
+      _$GuardianChildFromJson(json);
+
+  String get displayName => '$firstName $lastName'.trim();
+}