added guardian login with views for their assigned childs

lib/state/app/modules/app_modules.dart

@@ -3,8 +3,11 @@ import 'package:flutter/material.dart';
 import 'package:flutter_bloc/flutter_bloc.dart';
 import 'package:persistent_bottom_nav_bar_v2/persistent_bottom_nav_bar_v2.dart';
 
+import '../../../access/access_requirement.dart';
 import '../../../api/marianumconnect/queries/get_breakers/get_breakers_response.dart';
 import '../../../routing/app_routes.dart';
+import '../../../session/session.dart';
+import '../../../session/session_manager.dart';
 import '../../../storage/modules_settings.dart';
 import '../../../view/pages/absence_report/absence_report_view.dart';
 import '../../../view/pages/files/files.dart';
@@ -38,6 +41,16 @@ class AppModule {
     required this.create,
   });
 
+  /// Backend identities each module needs. Modules without an entry work for
+  /// every session.
+  static const Map<Modules, Set<AccessRequirement>> requirements = {
+    Modules.talk: {AccessRequirement.nextcloud},
+    Modules.files: {AccessRequirement.nextcloud},
+  };
+
+  static bool isAvailableFor(Modules module, Session? session) =>
+      (requirements[module] ?? const {}).areMetBy(session);
+
   static Map<Modules, AppModule> modules(
     BuildContext context, {
     bool showFiltered = false,
@@ -146,6 +159,9 @@ class AppModule {
       ),
     };
 
+    final session = SessionManager().current;
+    available.removeWhere((key, _) => !isAvailableFor(key, session));
+
     if (!showFiltered) {
       available.removeWhere(
         (key, value) =>
@@ -177,9 +193,7 @@ class AppModule {
     for (final missing in Modules.values) {
       if (!seen.add(missing)) continue;
       var insertAt = 0;
-      for (final predecessor in Modules.values.takeWhile(
-        (m) => m != missing,
-      )) {
+      for (final predecessor in Modules.values.takeWhile((m) => m != missing)) {
         final pos = order.indexOf(predecessor);
         if (pos >= insertAt) insertAt = pos + 1;
       }