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_response.dart

@@ -1,12 +1,14 @@
 import 'package:json_annotation/json_annotation.dart';
 
 import '../../../api_response.dart';
+import '../../../json_lenient.dart';
 import '../chat/get_chat_response.dart';
 
 part 'get_room_response.g.dart';
 
 @JsonSerializable(explicitToJson: true)
 class GetRoomResponse extends ApiResponse {
+  @JsonKey(fromJson: _roomsFromJson)
   Set<GetRoomResponseObject> data;
 
   GetRoomResponse(this.data);
@@ -33,10 +35,14 @@ class GetRoomResponse extends ApiResponse {
   }
 }
 
+Set<GetRoomResponseObject> _roomsFromJson(Object? raw) =>
+    decodeSetLenient(raw, GetRoomResponseObject.fromJson, what: 'room');
+
 @JsonSerializable(explicitToJson: true)
 class GetRoomResponseObject {
   int id;
   String token;
+  @JsonKey(unknownEnumValue: GetRoomResponseObjectConversationType.unknown)
   GetRoomResponseObjectConversationType type;
   String name;
   String displayName;
@@ -55,13 +61,20 @@ class GetRoomResponseObject {
   bool canLeaveConversation;
   int lastActivity;
   bool isFavorite;
+  @JsonKey(
+    unknownEnumValue:
+        GetRoomResponseObjectParticipantNotificationLevel.defaultLevel,
+  )
   GetRoomResponseObjectParticipantNotificationLevel notificationLevel;
   int unreadMessages;
   bool unreadMention;
   bool unreadMentionDirect;
   int lastReadMessage;
   int lastCommonReadMessage;
-  GetChatResponseObject lastMessage;
+
+  /// Omitted by the server for rooms without a visible message (empty room,
+  /// last message expired or hidden from this user, federated conversation).
+  GetChatResponseObject? lastMessage;
   String? status;
   String? statusIcon;
   String? statusMessage;
@@ -117,6 +130,9 @@ enum GetRoomResponseObjectConversationType {
   deleted,
   @JsonValue(6)
   noteToSelf,
+
+  /// Fallback for types this app does not know yet; treated like a group.
+  unknown,
 }
 
 enum GetRoomResponseObjectParticipantNotificationLevel {
@@ -147,6 +163,17 @@ enum GetRoomResponseObjectMessageActorType {
   bot,
   @JsonValue('bridged')
   bridge,
+  @JsonValue('groups')
+  group,
+  @JsonValue('emails')
+  email,
+  @JsonValue('circles')
+  circle,
+  @JsonValue('federated_users')
+  federatedUser,
+  @JsonValue('phones')
+  phone,
+  unknown,
 }
 
 enum GetRoomResponseObjectMessageType {
@@ -160,4 +187,8 @@ enum GetRoomResponseObjectMessageType {
   system,
   @JsonValue('command')
   command,
+
+  /// Fallback for types this app does not know yet (e.g. call recordings);
+  /// rendered like a plain comment.
+  unknown,
 }