@Override
    public ProjectedLayout getFieldLayout(OrcColumn orcColumn) {
      int fieldId = getIcebergFieldId(orcColumn);
      return projectedLayoutForFieldId.getOrDefault(fieldId, fullyProjectedLayout());
    }
Create a new NameMapping with the same names but converted to lowercase.

@param nameMapping The original NameMapping, potentially containing non-lowercase characters
amoro-format-mixed/amoro-mixed-trino/src/main/java/org/apache/amoro/trino/unkeyed/IcebergPageSourceProvider.java