Function validate_and_coerce_rows 

pub fn validate_and_coerce_rows(
    rows: &[Params],
    table: &Table,
) -> Result<Vec<Vec<Value>>>

Validate and coerce all rows for a table in columnar batch mode.

Processes all rows at once by:

1. Collecting params into columnar format
2. Coercing each column’s data in one batch using cast_column_data
3. Extracting coerced values back to row format

Returns Vec<Vec<Value>> where outer vec is rows, inner is column values in table column order.