Function run 

pub fn run<A: Application>(
    consumer: Consumer<OutputSlot<A::Report, A::QueryResponse>>,
    control_rx: Receiver<ControlEvent>,
    config: Response<A>,
    shutdown: &AtomicBool,
)

Run the io_uring response stage loop. Blocks the calling thread until shutdown.

Consumes from the output SPSC, waits for durability confirmation, and sends responses via io_uring SEND.

Durability gating: every gate iteration reads the journal cursor (primary persisted) plus per-slot replica cursors (in-memory and persisted) from replication_metrics and feeds them through the configured Policy. See [evaluate_durability].