fix(nats): use fetch().expires(30s) instead of messages() — without expires NATS returns empty immediately

crates/adapters/nats/src/lib.rs

@@ -137,10 +137,19 @@ impl MessageSource for NatsMessageSource {
             tracing::info!("NATS pull consumer ready");
 
             loop {
-                let mut messages = match consumer.messages().await {
+                // fetch().expires() keeps the request open server-side until messages arrive
+                // (up to 30 s), then the batch ends and we loop. Without expires, the fetch
+                // returns immediately with zero messages when the queue is empty.
+                let mut messages = match consumer
+                    .fetch()
+                    .max_messages(100)
+                    .expires(std::time::Duration::from_secs(30))
+                    .messages()
+                    .await
+                {
                     Ok(m) => m,
                     Err(e) => {
-                        tracing::error!("NATS consumer.messages() failed: {e}");
+                        tracing::error!("NATS fetch failed: {e}");
                         let _ = tx.send(Err(DomainError::Internal(e.to_string()))).await;
                         return;
                     }