Function map_cdf_to_changelog 

pub fn map_cdf_to_changelog(
    batch: &RecordBatch,
) -> Result<RecordBatch, ConnectorError>

Maps Delta CDF rows to the canonical signed-weight changelog and drops CDF metadata columns (_change_type, _commit_version, _commit_timestamp).

Errors

Returns ConnectorError::ReadError when CDF metadata is missing or invalid, or when the output batch cannot be built.