fix(relay): drop the outbox method the lifecycle merge orphaned

The union of adv3-map-composed and relay-lifecycle-fences kept a
flushRevokeOutbox that reads this.revokeOutbox/this.flushRevoke, both of
which relay-lifecycle-fences moved into the coordinator. Typecheck-only
break, invisible on either branch alone.

src/main/runtime/relay/desktop-relay-service.ts

@@ -251,12 +251,6 @@ export class DesktopRelayService {
     }
   }
 
-  private async flushRevokeOutbox(broker: RelaySessionBroker): Promise<void> {
-    for (const item of this.revokeOutbox.pendingFor(broker.ownerIdentityKey, broker.hostId)) {
-      await this.flushRevoke(broker, item)
-    }
-  }
-
   private requireMobileDevice(deviceId: string): void {
     if (this.runtimeRpc.getDeviceRegistry()?.getDevice(deviceId)?.scope !== 'mobile') {
       throw new Error('mobile_device_not_found')