migrated timetable integration from WebUntis to the MarianumConnect API, implementing a Dio-based client with bearer token authentication, background session validation, and auto-refresh logic.

lib/api/marianumconnect/marianumconnect_api.dart

@@ -0,0 +1,30 @@
+import 'package:dio/dio.dart';
+
+import 'auth/auth_interceptor.dart';
+
+/// Singleton dio instance for the Marianum-Connect mobile API. Wired with the
+/// bearer auth interceptor at startup; the base URL is resolved per request
+/// through [MarianumConnectEndpoint] so settings changes take effect without
+/// recreating the client.
+class MarianumConnectApi {
+  static const Duration _connectTimeout = Duration(seconds: 10);
+  static const Duration _receiveTimeout = Duration(seconds: 20);
+
+  static final Dio _instance = _build();
+
+  static Dio dio() => _instance;
+
+  static Dio _build() {
+    final dio = Dio(
+      BaseOptions(
+        connectTimeout: _connectTimeout,
+        sendTimeout: _connectTimeout,
+        receiveTimeout: _receiveTimeout,
+        responseType: ResponseType.json,
+        contentType: 'application/json',
+      ),
+    );
+    dio.interceptors.add(MarianumConnectAuthInterceptor());
+    return dio;
+  }
+}