migrated the breaker system to MarianumConnect and refactored the API response to a rule-based model with support for version-specific blocks using maxBuild.

lib/api/marianumconnect/queries/get_breakers/get_breakers.dart

@@ -0,0 +1,26 @@
+import 'package:dio/dio.dart';
+
+import '../../errors/marianumconnect_error.dart';
+import '../../marianumconnect_api.dart';
+import '../../marianumconnect_endpoint.dart';
+import 'get_breakers_response.dart';
+
+/// Fetches the app maintenance breaker rules from `GET /api/mobile/v1/breaker`.
+/// The endpoint is public: the bearer token is attached if present but not
+/// required, so this also works before login (e.g. to block the whole app).
+class GetBreakers {
+  final Dio _dio;
+
+  GetBreakers({Dio? dio}) : _dio = dio ?? MarianumConnectApi.dio();
+
+  Future<GetBreakersResponse> run() async {
+    try {
+      final response = await _dio.get<Map<String, dynamic>>(
+        MarianumConnectEndpoint.resolve('breaker'),
+      );
+      return GetBreakersResponse.fromJson(response.data!);
+    } on DioException catch (e) {
+      throw mapMarianumConnectError(e);
+    }
+  }
+}

lib/api/marianumconnect/queries/get_breakers/get_breakers_cache.dart

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+import '../../../request_cache.dart';
+import 'get_breakers.dart';
+import 'get_breakers_response.dart';
+
+class GetBreakersCache extends SimpleCache<GetBreakersResponse> {
+  GetBreakersCache({super.onUpdate, super.renew, super.onError})
+    : super(
+        cacheTime: RequestCache.cacheMinute,
+        loader: () => GetBreakers().run(),
+        fromJson: GetBreakersResponse.fromJson,
+      ) {
+    start('breakers');
+  }
+}

lib/api/marianumconnect/queries/get_breakers/get_breakers_response.dart

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+import 'package:json_annotation/json_annotation.dart';
+
+import '../../../api_response.dart';
+
+part 'get_breakers_response.g.dart';
+
+/// App maintenance breaker rules delivered by
+/// `GET /api/mobile/v1/breaker`. Each rule blocks the listed [areas] with a
+/// [message]; [BreakerRule.maxBuild] optionally scopes it to old app builds.
+///
+/// [rules] defaults to empty so a payload in the pre-migration shape
+/// (`global`/`regional`) — which may still sit in the hydrated/cache store
+/// after an update — parses to "nothing blocked" instead of throwing.
+@JsonSerializable(explicitToJson: true)
+class GetBreakersResponse extends ApiResponse {
+  @JsonKey(defaultValue: [])
+  List<BreakerRule> rules;
+
+  GetBreakersResponse(this.rules);
+
+  factory GetBreakersResponse.fromJson(Map<String, dynamic> json) =>
+      _$GetBreakersResponseFromJson(json);
+  Map<String, dynamic> toJson() => _$GetBreakersResponseToJson(this);
+}
+
+@JsonSerializable()
+class BreakerRule {
+  List<BreakerArea> areas;
+  String message;
+
+  /// When set, the rule only applies to app builds whose build number is
+  /// &le; [maxBuild] (force-update of old versions). `null` = every build.
+  int? maxBuild;
+
+  BreakerRule(this.areas, this.message, this.maxBuild);
+
+  factory BreakerRule.fromJson(Map<String, dynamic> json) =>
+      _$BreakerRuleFromJson(json);
+  Map<String, dynamic> toJson() => _$BreakerRuleToJson(this);
+}
+
+/// Blockable areas of the app. Each app module maps itself to one of these via
+/// its `breakerArea` (see `app_modules.dart`). Must stay in sync with the
+/// backend enum `BreakerArea` in the MarianumConnect `marMobileApi` service —
+/// the backend only offers these values in the admin UI, so when a new blockable
+/// module is added here, add the matching value on the backend too.
+enum BreakerArea {
+  @JsonValue('GLOBAL')
+  global,
+  @JsonValue('TIMETABLE')
+  timetable,
+  @JsonValue('TALK')
+  talk,
+  @JsonValue('FILES')
+  files,
+  @JsonValue('NEWS')
+  news,
+  @JsonValue('ROOMPLAN')
+  roomPlan,
+  @JsonValue('GRADES')
+  grades,
+  @JsonValue('HOLIDAYS')
+  holidays,
+  @JsonValue('DATES')
+  dates,
+  @JsonValue('FEEDBACK')
+  feedback,
+  @JsonValue('MORE')
+  more,
+}

lib/api/marianumconnect/queries/get_breakers/get_breakers_response.g.dart

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+// GENERATED CODE - DO NOT MODIFY BY HAND
+
+part of 'get_breakers_response.dart';
+
+// **************************************************************************
+// JsonSerializableGenerator
+// **************************************************************************
+
+GetBreakersResponse _$GetBreakersResponseFromJson(Map<String, dynamic> json) =>
+    GetBreakersResponse(
+        (json['rules'] as List<dynamic>?)
+                ?.map((e) => BreakerRule.fromJson(e as Map<String, dynamic>))
+                .toList() ??
+            [],
+      )
+      ..headers = (json['headers'] as Map<String, dynamic>?)?.map(
+        (k, e) => MapEntry(k, e as String),
+      );
+
+Map<String, dynamic> _$GetBreakersResponseToJson(
+  GetBreakersResponse instance,
+) => <String, dynamic>{
+  'headers': ?instance.headers,
+  'rules': instance.rules.map((e) => e.toJson()).toList(),
+};
+
+BreakerRule _$BreakerRuleFromJson(Map<String, dynamic> json) => BreakerRule(
+  (json['areas'] as List<dynamic>)
+      .map((e) => $enumDecode(_$BreakerAreaEnumMap, e))
+      .toList(),
+  json['message'] as String,
+  (json['maxBuild'] as num?)?.toInt(),
+);
+
+Map<String, dynamic> _$BreakerRuleToJson(BreakerRule instance) =>
+    <String, dynamic>{
+      'areas': instance.areas.map((e) => _$BreakerAreaEnumMap[e]!).toList(),
+      'message': instance.message,
+      'maxBuild': instance.maxBuild,
+    };
+
+const _$BreakerAreaEnumMap = {
+  BreakerArea.global: 'GLOBAL',
+  BreakerArea.timetable: 'TIMETABLE',
+  BreakerArea.talk: 'TALK',
+  BreakerArea.files: 'FILES',
+  BreakerArea.news: 'NEWS',
+  BreakerArea.roomPlan: 'ROOMPLAN',
+  BreakerArea.grades: 'GRADES',
+  BreakerArea.holidays: 'HOLIDAYS',
+  BreakerArea.dates: 'DATES',
+  BreakerArea.feedback: 'FEEDBACK',
+  BreakerArea.more: 'MORE',
+};