Function export_data 

pub async fn export_data(
    database: &Database,
    source: &str,
    file: &Path,
    format: ExportFormat,
    query_filter: Option<&str>,
    limit: Option<usize>,
    quiet: bool,
) -> Result<()>

Export data using true streaming execution (Issue #280)

This function uses execute_streaming() to process rows incrementally, avoiding the need to materialize all query results in memory at once.