added guardian login with views for their assigned childs

lib/view/login/nextcloud_login_flow_page.dart

@@ -7,7 +7,7 @@ import 'package:flutter/material.dart';
 import '../../api/errors/error_mapper.dart';
 import '../../api/marianumcloud/app_password/delete_app_password.dart';
 import '../../api/marianumcloud/login_flow/login_flow_api.dart';
-import '../../model/account_data.dart';
+import '../../session/session_manager.dart';
 import '../../utils/url_opener.dart';
 import '../../widget/app_progress_indicator.dart';
 
@@ -19,7 +19,7 @@ enum _FlowStep { primary, talk }
 
 /// Runs the Nextcloud Login Flow v2: opens the browser login, polls until the
 /// user confirmed it there (2FA happens inside the browser) and adopts the
-/// returned app password via [AccountData.setLoginFlow]. A second, skippable
+/// returned app password via [SessionManager.setLoginFlow]. A second, skippable
 /// pass mints the Talk app password so flow accounts keep BOTH push
 /// subscriptions (see PushRegistrationType). Pops `true` once the primary
 /// credential was adopted, `false`/`null` when the user backs out before that.
@@ -104,7 +104,7 @@ class _NextcloudLoginFlowPageState extends State<NextcloudLoginFlowPage>
       final credentials = await _api.poll(flow);
       if (credentials == null || _finished || !mounted) return;
       if (!LoginFlowApi.loginNameMatches(
-        expected: AccountData().getUsername(),
+        expected: SessionManager().requireNextcloud().username,
         actual: credentials.loginName,
       )) {
         _timer?.cancel();
@@ -120,7 +120,7 @@ class _NextcloudLoginFlowPageState extends State<NextcloudLoginFlowPage>
       }
       switch (_step) {
         case _FlowStep.primary:
-          await AccountData().setLoginFlow(credentials.appPassword);
+          await SessionManager().setLoginFlow(credentials.appPassword);
           if (!mounted) return;
           // Zweite Freigabe direkt anstoßen: die Browser-Session besteht
           // bereits, es fehlt nur noch der Grant-Tipp.
@@ -129,7 +129,7 @@ class _NextcloudLoginFlowPageState extends State<NextcloudLoginFlowPage>
         case _FlowStep.talk:
           _finished = true;
           _timer?.cancel();
-          await AccountData().setAppPasswordTalk(credentials.appPassword);
+          await SessionManager().setAppPasswordTalk(credentials.appPassword);
           if (!mounted) return;
           Navigator.of(context).pop(true);
       }