Function pick_automatic 

async fn pick_automatic(
    region: &CompactionRegion,
    history: &mut PickHistory,
    max_outputs: Option<usize>,
    time_range: Option<TimestampRange>,
) -> Result<Option<PickerOutput>>

Scheduler policy applied between stateless discovery and semantic closure. Runs on the planning runtime with a private history snapshot, never on the worker or through a shared mutex. Stale results cannot mutate resident state.