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/marianumconnect/queries/get_ticker/get_ticker_response.g.dart

@@ -7,14 +7,20 @@ part of 'get_ticker_response.dart';
 // **************************************************************************
 
 TickerResponse _$TickerResponseFromJson(Map<String, dynamic> json) =>
-    TickerResponse(
-      schemaVersion: (json['schemaVersion'] as num?)?.toInt() ?? 1,
-      available: json['available'] as bool? ?? false,
-      hash: json['hash'] as String?,
-      publishedAt: json['publishedAt'] as String?,
-      webUrl: json['webUrl'] as String? ?? '/ticker',
-      content: json['content'] as Map<String, dynamic>?,
-    );
+    $checkedCreate('TickerResponse', json, ($checkedConvert) {
+      final val = TickerResponse(
+        schemaVersion: $checkedConvert(
+          'schemaVersion',
+          (v) => (v as num?)?.toInt() ?? 1,
+        ),
+        available: $checkedConvert('available', (v) => v as bool? ?? false),
+        hash: $checkedConvert('hash', (v) => v as String?),
+        publishedAt: $checkedConvert('publishedAt', (v) => v as String?),
+        webUrl: $checkedConvert('webUrl', (v) => v as String? ?? '/ticker'),
+        content: $checkedConvert('content', (v) => v as Map<String, dynamic>?),
+      );
+      return val;
+    });
 
 Map<String, dynamic> _$TickerResponseToJson(TickerResponse instance) =>
     <String, dynamic>{