perf: batch gateway submits and isolate callbacks

api/src/open-api/open-api.service.ts

@@ -55,6 +55,10 @@ export class OpenApiService implements OnModuleInit, OnModuleDestroy {
   onModuleInit() {
     const connection = bullmqConnection();
     this.queue = new Queue(WEBHOOK_QUEUE, { connection });
+    // The isolated Gateway callback process only enqueues customer callbacks.
+    // Delivery remains owned by the main API process so callback DB/HTTP capacity
+    // cannot be consumed by slow customer webhook endpoints.
+    if (process.env.CMPP_PROCESS_ROLE === 'callback') return;
     this.worker = new Worker(WEBHOOK_QUEUE, (job) => this.deliverWebhook(job.data.deliveryId), { connection, concurrency: 10 });
   }