Release IKAR 1.0.7: port navigation and sharing improvements, harden calls

lib/backend/modules/messages.dart

@@ -201,7 +201,8 @@ class TranscriptionCache {
     } else {
       _expanded.remove(messageId);
     }
-    for (final listener in _listeners[messageId]?.toList() ?? <VoidCallback>[]) {
+    for (final listener
+        in _listeners[messageId]?.toList() ?? <VoidCallback>[]) {
       listener();
     }
   }
@@ -789,6 +790,23 @@ class MessagesModule {
   }
 
   // #***! история с сервера
+  Future<CachedMessage?> fetchMessage(
+    int accountId,
+    int chatId,
+    String id,
+  ) async {
+    final messageId = int.tryParse(id);
+    if (messageId == null) return null;
+    final response = await _api.sendRequest(Opcode.msgGet, {
+      'chatId': chatId,
+      'messageId': messageId,
+    });
+    if (!response.isOk || response.payload is! Map) return null;
+    final raw = (response.payload as Map)['message'];
+    if (raw is! Map) return null;
+    return _parseMessage(raw, accountId, chatId);
+  }
+
   Future<List<CachedMessage>> fetchHistory(
     int accountId,
     int chatId, {

lib/backend/modules/pending_message_deletions.dart

@@ -0,0 +1,24 @@
+import 'package:flutter/foundation.dart';
+
+/// Pending UI removals are scoped to an account as well as a chat.
+class PendingMessageDeletions extends ChangeNotifier {
+  PendingMessageDeletions();
+  static final instance = PendingMessageDeletions();
+  final Map<(int, int), Set<String>> _pending = {};
+
+  bool contains(int accountId, int chatId, String id) =>
+      _pending[(accountId, chatId)]?.contains(id) ?? false;
+
+  void hold(int accountId, int chatId, Iterable<String> ids) {
+    _pending.putIfAbsent((accountId, chatId), () => {}).addAll(ids);
+    notifyListeners();
+  }
+
+  void release(int accountId, int chatId, Iterable<String> ids) {
+    final pending = _pending[(accountId, chatId)];
+    if (pending == null) return;
+    pending.removeAll(ids);
+    if (pending.isEmpty) _pending.remove((accountId, chatId));
+    notifyListeners();
+  }
+}