Method resolveDiskFileChange

app/src/DataModel/ProjectModel.cpp:7774–7817

* @brief Debounced watcher handler: ignores self-saves (hash unchanged), flags deletion, * and prompts to reload when another program modified the project file. */

 *        and prompts to reload when another program modified the project file.
 */
void DataModel::ProjectModel::resolveDiskFileChange()
{
  m_diskCheckPending = false;
  if (m_diskPromptActive || m_filePath.isEmpty())
    return;

  if (!QFile::exists(m_filePath)) {
    m_diskFileHash.clear();
    m_modified = true;
    Q_EMIT modifiedChanged();
    Q_EMIT projectFileChangedOnDisk();
    DataModel::NotificationCenter::instance().postWarning(
      QStringLiteral("ProjectModel"),
      tr("Project file removed from disk"),
      tr("%1 was deleted or renamed by another program. Save the project to recreate it.")
        .arg(jsonFileName()));
    return;
  }

  if (!m_fileWatcher->files().contains(m_filePath))
    m_fileWatcher->addPath(m_filePath);

  const auto hash = hashProjectFile(m_filePath);
  if (hash.isEmpty() || hash == m_diskFileHash)
    return;

  m_diskFileHash = hash;
  Q_EMIT projectFileChangedOnDisk();

  if (m_suppressMessageBoxes) {
    qWarning() << "[ProjectModel] Project file changed on disk; keeping in-memory state";
    m_modified = true;
    Q_EMIT modifiedChanged();
    DataModel::NotificationCenter::instance().postWarning(
      QStringLiteral("ProjectModel"),
      tr("Project file changed on disk"),
      tr("%1 was modified by another program. The in-memory project was kept; reopen the "
         "file to load the external changes.")
        .arg(jsonFileName()));
    return;
  }

  promptDiskFileReload();
}

/**
 * @brief Asks whether to reload the externally-modified project file; declining keeps the