Function execute_scatter_gather 

pub async fn execute_scatter_gather(
    fighters: &[FighterId],
    task: &str,
    router: &MessageRouter,
    coordinator: FighterId,
    _timeout: Duration,
    criteria: &SelectionCriteria,
) -> PunchResult<Option<ScatterResponse>>

Execute the scatter-gather pattern: send a task to all capable fighters, wait for responses (with configurable timeout), and select the best result based on SelectionCriteria.