Function rewrite_dictionary_string_regex 

fn rewrite_dictionary_string_regex(
    binary: BinaryExpr,
    schema: &DFSchemaRef,
) -> Result<Option<Expr>>

Removes the string coercion/schema-reconciliation cast present before physical regex planning.

Keeping the dictionary input lets DataFusion’s physical regex kernel evaluate scalar patterns against dictionary values instead of materializing the string column first.