Function get_output_column_names_for_dialect 

pub fn get_output_column_names_for_dialect(
    expr: &Expression,
    dialect: Option<DialectType>,
) -> Vec<String>

Collect projected output column names using dialect-specific set-operation alignment rules.

This differs from get_output_column_names only for name-aligned set operations. When an output shape is not statically knowable (for example an unresolved wildcard), it preserves the existing leftmost-branch behavior.