Function execute_cql_string 

pub async fn execute_cql_string(
    session: &mut CqlSession,
    config: &MergedConfig,
    colorizer: &CqlColorizer,
    cql_string: &str,
    writer: &mut dyn Write,
) -> i32

Execute a CQL string from the -e flag (semicolon-separated statements).

All output is written to writer; errors go to stderr. Returns exit code: 0 on success, 1 on any CQL error.