fixed stalled requests after app resume

lib/api/marianumcloud/autocomplete/autocomplete_api.dart

@@ -4,6 +4,7 @@ import 'package:http/http.dart' as http;
 
 import '../../../model/endpoint_data.dart';
 import '../../errors/server_exception.dart';
+import '../../http_errors.dart';
 import '../nextcloud_ocs.dart';
 import 'autocomplete_response.dart';
 
@@ -30,7 +31,12 @@ class AutocompleteApi {
         'limit': '10',
       },
     );
-    final response = await http.get(uri, headers: NextcloudOcs.headers());
+    final response = (await sendGuarded(
+      'Autocomplete $uri',
+      () => http
+          .get(uri, headers: NextcloudOcs.headers())
+          .timeout(const Duration(seconds: 20)),
+    ))!;
     if (response.statusCode != HttpStatus.ok) {
       throw ServerException(
         statusCode: response.statusCode,

lib/api/marianumcloud/talk/talk_api.dart

@@ -12,6 +12,10 @@ import '../nextcloud_ocs.dart';
 import 'talk_error.dart';
 
 abstract class TalkApi<T extends ApiResponse?> {
+  // package:http has no timeout of its own; a request stuck on a dead
+  // connection (e.g. one started right before a suspend) would spin forever.
+  static const Duration _timeout = Duration(seconds: 30);
+
   String path;
   ApiParams? body;
   Map<String, String>? headers;
@@ -35,7 +39,7 @@ abstract class TalkApi<T extends ApiResponse?> {
 
     final data = await sendGuarded(
       'Talk $endpoint',
-      () => request(endpoint, body, mergedHeaders),
+      () => request(endpoint, body, mergedHeaders)?.timeout(_timeout),
     );
     if (data == null) {
       throw const NetworkException(

lib/api/marianumconnect/marianumconnect_api.dart

@@ -16,6 +16,16 @@ class MarianumConnectApi {
 
   static Dio dio() => _instance;
 
+  /// Drops the pooled keep-alive sockets. After a suspend the OS or a NAT
+  /// has usually killed them already, but dart:io only notices once a request
+  /// is written into one — which then hangs until [_receiveTimeout].
+  /// In-flight requests finish on the old adapter.
+  static void resetConnections() {
+    final stale = _instance.httpClientAdapter;
+    _instance.httpClientAdapter = HttpClientAdapter();
+    stale.close();
+  }
+
   /// A fresh dio with the standard JSON options but no interceptors — used by
   /// the auth queries (login/verify) that must bypass the bearer/demo
   /// interceptors to avoid a re-auth loop.