added guardian login with views for their assigned childs

lib/view/login/login.dart

@@ -3,6 +3,9 @@ import 'dart:async';
 import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 
+import '../../api/marianumconnect/marianumconnect_endpoint.dart' as mc;
+import '../../auth_link/guardian_link_listener.dart';
+import '../../auth_link/guardian_login_link.dart';
 import '../../background/widget_background_task.dart';
 import '../../state/app/modules/account/bloc/account_bloc.dart';
 import '../../state/app/modules/account/bloc/account_state.dart';
@@ -12,8 +15,11 @@ import '../../storage/settings.dart' as model;
 import '../../theming/light_app_theme.dart';
 import '../../utils/haptics.dart';
 import '../pages/settings/widgets/endpoint_picker.dart';
+import 'guardian_login_controller.dart';
 import 'login_controller.dart';
 import 'post_login_splash.dart';
+import 'widgets/guardian_login_card.dart';
+import 'widgets/login_audience_card.dart';
 import 'widgets/login_branding.dart';
 import 'widgets/login_card.dart';
 
@@ -28,12 +34,45 @@ class _LoginState extends State<Login> with SingleTickerProviderStateMixin {
   static const _marianumRed = LightAppTheme.marianumRed;
 
   final LoginController _controller = LoginController();
+  final GuardianLoginController _guardianController = GuardianLoginController();
+  late final Future<void> _guardianRestored;
+
+  /// Null while the user has not picked who is signing in.
+  LoginAudience? _audience;
   late final AnimationController _fade = AnimationController(
     vsync: this,
     duration: const Duration(milliseconds: 450),
     value: 1,
   );
 
+  @override
+  void initState() {
+    super.initState();
+    _guardianRestored = _guardianController.restore().then((_) {
+      if (!mounted || _guardianController.pending == null) return;
+      setState(() => _audience = LoginAudience.guardian);
+    });
+    GuardianLinkListener.pending.addListener(_consumeGuardianLink);
+    _consumeGuardianLink();
+  }
+
+  /// A tapped mail link finishes the guardian login without typing the code.
+  Future<void> _consumeGuardianLink() async {
+    final uri = GuardianLinkListener.pending.value;
+    if (uri == null) return;
+    GuardianLinkListener.clear();
+    final link = GuardianLoginLink.parse(
+      uri,
+      apiBase: Uri.parse(mc.MarianumConnectEndpoint.current()),
+    );
+    if (link == null) return;
+    await _guardianRestored;
+    if (!mounted) return;
+    setState(() => _audience = LoginAudience.guardian);
+    final signedIn = await _guardianController.submitLink(link);
+    if (signedIn && mounted) _onLoginSuccess();
+  }
+
   @override
   void didChangeDependencies() {
     super.didChangeDependencies();
@@ -43,8 +82,10 @@ class _LoginState extends State<Login> with SingleTickerProviderStateMixin {
 
   @override
   void dispose() {
+    GuardianLinkListener.pending.removeListener(_consumeGuardianLink);
     _fade.dispose();
     _controller.dispose();
+    _guardianController.dispose();
     super.dispose();
   }
 
@@ -64,6 +105,20 @@ class _LoginState extends State<Login> with SingleTickerProviderStateMixin {
     });
   }
 
+  Widget _buildCard() => switch (_audience) {
+    null => LoginAudienceCard(
+      onSelected: (choice) => setState(() => _audience = choice),
+    ),
+    LoginAudience.school => LoginCard(
+      controller: _controller,
+      onSuccess: _onLoginSuccess,
+    ),
+    LoginAudience.guardian => GuardianLoginCard(
+      controller: _guardianController,
+      onSuccess: _onLoginSuccess,
+    ),
+  };
+
   @override
   Widget build(BuildContext context) => Scaffold(
     backgroundColor: _marianumRed,
@@ -89,12 +144,33 @@ class _LoginState extends State<Login> with SingleTickerProviderStateMixin {
                       children: [
                         const LoginHeader(),
                         const SizedBox(height: 28),
-                        LoginCard(
-                          controller: _controller,
-                          onSuccess: _onLoginSuccess,
-                        ),
-                        const SizedBox(height: 18),
-                        const LoginDisclaimer(),
+                        _buildCard(),
+                        if (_audience != null)
+                          Padding(
+                            padding: const EdgeInsets.only(top: 8),
+                            // Leaving mid-request would drop the form that
+                            // receives the result, so it is disabled then.
+                            child: ListenableBuilder(
+                              listenable: Listenable.merge([
+                                _controller,
+                                _guardianController,
+                              ]),
+                              builder: (context, _) => TextButton.icon(
+                                style: TextButton.styleFrom(
+                                  foregroundColor: Colors.white,
+                                ),
+                                icon: const Icon(Icons.arrow_back, size: 18),
+                                label: const Text('Zurück zur Auswahl'),
+                                onPressed:
+                                    _controller.loading ||
+                                        _guardianController.loading
+                                    ? null
+                                    : () => setState(() => _audience = null),
+                              ),
+                            ),
+                          )
+                        else
+                          const SizedBox(height: 12),
                       ],
                     ),
                     const Column(