Apply task-scoped media preparation events to the shared Qt composer

tools/chatgui/src/messagelist.cpp

@@ -1054,6 +1054,15 @@ void MessageList::requestDmMessages(const QString& channelId) {
     gui_bridge_post_uasync_fn(dm_messages_trampoline, req);
 }
 
+void MessageList::onAttachmentPreparation(const uint8_t* data, int len) {
+    if (!data || len < 18 || len != 18 + data[0] || data[len - 1] > 2) {
+        DEBUG_ERROR(DEBUG_CATEGORY_MEDIA, "Invalid attachment preparation event bytes=%d", len); return;
+    }
+    int length = data[0];
+    m_inputBar->updatePreparation(QString::fromUtf8((const char*)data + 1, length),
+        QByteArray((const char*)data + 1 + length, 16), data[len - 1]);
+}
+
 void MessageList::onDmMessages(const uint8_t* data, int len) {
     if (len < 3) return;
     uint8_t cl = data[0];