hardened API decoding against server fields the models did not expect

The Talk room list crashed for a new account because the server omits
lastMessage for rooms without a visible message and the model required it.
Beyond that single field, a review of the Talk models against the OpenAPI
spec of the installed version (23.0.8) found the same crash class in several
places: closed enums over open server values (inCall bitmask, rich-object
types, actor and message types), a deleted parent sent as {id, deleted},
and the autocomplete status arriving as an object.

- json_serializable `checked: true`: decode errors now name class and field
- lists (rooms, messages, participants, autocomplete) decode per entry;
  a malformed entry is skipped and reported via ClientErrorReporter
- unknownEnumValue fallbacks for all response enums of Talk and breakers
- lastMessage nullable; inCall as bitmask; deleted parent placeholder;
  autocomplete status object/string; fixed shareWithDisplayNameUnique key
- GetRoomParams no longer sends null query parameters

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HrepDTL4qDe35TuS29sLW3

lib/api/marianumcloud/talk/talk_api.dart

@@ -8,6 +8,8 @@ import '../../errors/network_exception.dart';
 import '../../errors/parse_exception.dart';
 import '../../errors/talk_exception.dart';
 import '../../http_errors.dart';
+import '../../json_lenient.dart';
+import '../../marianumconnect/queries/report_client_error/client_error_reporter.dart';
 import '../nextcloud_ocs.dart';
 import 'talk_error.dart';
 
@@ -73,12 +75,17 @@ abstract class TalkApi<T extends ApiResponse?> {
       throwForStatus(status, detail);
     }
 
+    final T assembled;
     try {
-      final assembled = await assembleAsync(data.body);
-      assembled?.headers = data.headers;
-      return assembled;
+      assembled = await assembleAsync(data.body);
     } catch (e) {
       throw ParseException(technicalDetails: 'Talk $endpoint assemble: $e');
     }
+    assembled?.headers = data.headers;
+    ClientErrorReporter.reportDecodeWarnings('Talk $path', [
+      ...?assembled?.parseWarnings,
+      ...drainDecodeWarnings(),
+    ]);
+    return assembled;
   }
 }