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/room/get_room_params.g.dart

@@ -7,22 +7,28 @@ part of 'get_room_params.dart';
 // **************************************************************************
 
 GetRoomParams _$GetRoomParamsFromJson(Map<String, dynamic> json) =>
-    GetRoomParams(
-      noStatusUpdate: $enumDecodeNullable(
-        _$GetRoomParamsStatusUpdateEnumMap,
-        json['noStatusUpdate'],
-      ),
-      includeStatus: json['includeStatus'] as bool?,
-      modifiedSince: (json['modifiedSince'] as num?)?.toInt(),
-    );
+    $checkedCreate('GetRoomParams', json, ($checkedConvert) {
+      final val = GetRoomParams(
+        noStatusUpdate: $checkedConvert(
+          'noStatusUpdate',
+          (v) => $enumDecodeNullable(_$GetRoomParamsStatusUpdateEnumMap, v),
+        ),
+        includeStatus: $checkedConvert('includeStatus', (v) => v as bool?),
+        modifiedSince: $checkedConvert(
+          'modifiedSince',
+          (v) => (v as num?)?.toInt(),
+        ),
+      );
+      return val;
+    });
 
-Map<String, dynamic> _$GetRoomParamsToJson(
-  GetRoomParams instance,
-) => <String, dynamic>{
-  'noStatusUpdate': _$GetRoomParamsStatusUpdateEnumMap[instance.noStatusUpdate],
-  'includeStatus': GetRoomParams._format(instance.includeStatus),
-  'modifiedSince': instance.modifiedSince,
-};
+Map<String, dynamic> _$GetRoomParamsToJson(GetRoomParams instance) =>
+    <String, dynamic>{
+      'noStatusUpdate':
+          ?_$GetRoomParamsStatusUpdateEnumMap[instance.noStatusUpdate],
+      'includeStatus': GetRoomParams._format(instance.includeStatus),
+      'modifiedSince': ?instance.modifiedSince,
+    };
 
 const _$GetRoomParamsStatusUpdateEnumMap = {
   GetRoomParamsStatusUpdate.defaults: 0,