Method datasetUpdate

app/src/API/Handlers/ProjectHandler.cpp:4967–5030

* @brief Patch any subset of dataset fields by groupId + datasetId; any applied field forces * the tree rebuild so the epoch-gated dashboard apply and editor reload fire. */

 *        the tree rebuild so the epoch-gated dashboard apply and editor reload fire.
 */
API::CommandResponse API::Handlers::ProjectHandler::datasetUpdate(const QString& id,
                                                                  const QJsonObject& params)
{
  if (!params.contains(QStringLiteral("groupId")))
    return CommandResponse::makeError(
      id, ErrorCode::MissingParam, QStringLiteral("Missing required parameter: groupId"));

  if (!params.contains(Keys::DatasetId))
    return CommandResponse::makeError(
      id, ErrorCode::MissingParam, QStringLiteral("Missing required parameter: datasetId"));

  const int groupId   = params.value(QStringLiteral("groupId")).toInt();
  const int datasetId = params.value(Keys::DatasetId).toInt();
  auto& project       = DataModel::ProjectModel::instance();
  const auto& groups  = project.groups();
  if (groupId < 0 || static_cast<size_t>(groupId) >= groups.size())
    return CommandResponse::makeError(
      id, ErrorCode::InvalidParam, QStringLiteral("Group id not found: %1").arg(groupId));

  const auto& datasets = groups[groupId].datasets;
  if (datasetId < 0 || static_cast<size_t>(datasetId) >= datasets.size())
    return CommandResponse::makeError(id,
                                      ErrorCode::InvalidParam,
                                      QStringLiteral("Dataset id not found: %1 in group %2")
                                        .arg(QString::number(datasetId), QString::number(groupId)));

  DataModel::Dataset d = datasets[datasetId];
  bool rebuildTree     = false;
  QSet<QString> consumed{
    QStringLiteral("groupId"), Keys::DatasetId, QStringLiteral("expectedProjectEpoch")};
  const auto identityKeyCount = consumed.size();
  const QString err           = applyDatasetUpdateParams(d, params, rebuildTree, consumed);
  if (!err.isEmpty())
    return CommandResponse::makeError(id, ErrorCode::InvalidParam, err);

  if (consumed.size() > identityKeyCount)
    rebuildTree = true;

  const auto preEpoch = captureProjectEpoch();
  project.updateDataset(groupId, datasetId, d, rebuildTree);

  QJsonObject result;
  result[QStringLiteral("groupId")] = groupId;
  result[Keys::DatasetId]           = datasetId;
  result[QStringLiteral("updated")] = true;

  appendUnknownFieldsWarning(result, params, consumed, QStringLiteral("project.dataset.update"));
  appendStaleProjectWarning(result, params, preEpoch);
  attachProjectEpoch(result);

  if (!d.transformCode.isEmpty() && d.transformLanguage != -1) {
    const auto warning = detectLanguageMismatch(d.transformCode, d.transformLanguage);
    if (!warning.isEmpty())
      result[QStringLiteral("warning")] = warning;
  }

  if (!d.transformCode.isEmpty() && !d.virtual_ && d.index <= 0)
    result[QStringLiteral("hint")] =