feat: NATS 连接与 JetStream 流引导（BPOS_EVT/CMD/DLQ）＋touch 发布

src/shared/bus/nats.ts

@@ -0,0 +1,28 @@
+import { connect } from 'nats';
+import type { NatsConnection } from 'nats';
+import { config } from '../config';
+
+let nc: NatsConnection | null = null;
+
+export async function getNats(): Promise<NatsConnection> {
+  if (nc && !nc.isClosed()) return nc;
+  nc = await connect({ servers: config.natsUrl, name: config.serviceName, timeout: 5000 });
+  return nc;
+}
+
+export async function checkNats(): Promise<'ok' | 'fail'> {
+  try {
+    const c = await getNats();
+    await c.flush();
+    return 'ok';
+  } catch {
+    return 'fail';
+  }
+}
+
+export async function closeNats(): Promise<void> {
+  if (nc) {
+    await nc.drain().catch(() => {});
+    nc = null;
+  }
+}