style: apply rustfmt to host shutdown changes

Co-authored-by: Claude <noreply@anthropic.com>

backend/crates/gateway-host/src/workers/mod.rs

@@ -116,7 +116,10 @@ impl WorkerSupervisor {
         let handles = std::mem::take(&mut *lock_unpoisoned(&self.handles));
         let deadline = tokio::time::Instant::now() + timeout;
         for (_, mut handle) in handles {
-            if tokio::time::timeout_at(deadline, &mut handle).await.is_err() {
+            if tokio::time::timeout_at(deadline, &mut handle)
+                .await
+                .is_err()
+            {
                 handle.abort();
                 let _ = handle.await;
             }

backend/crates/gateway-host/tests/workers/mod.rs

@@ -660,7 +660,9 @@ async fn shutdown_timeout_must_not_rejoin_workers_that_already_exited() {
     });
     let leases = Arc::new(FakeLeasePort::default());
     let supervisor = supervisor();
-    supervisor.start(plan, leases.clone()).expect("complete plan");
+    supervisor
+        .start(plan, leases.clone())
+        .expect("complete plan");
     hung.notification.notified().await;
     wait_until(|| cooperative.entered.load(Ordering::SeqCst) == ACTIVE_KINDS.len() - 1).await;