fix(nats): revert to consumer.messages() — fetch() defaults no_wait:true which skips empty queues

crates/adapters/nats/src/lib.rs

@@ -139,19 +139,14 @@ impl MessageSource for NatsMessageSource {
             tracing::info!("NATS pull consumer ready");
 
             loop {
-                // 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
-                {
+                // consumer.messages() uses long-poll (no no_wait flag) — NATS holds the
+                // request open and delivers messages as they arrive.
+                // fetch() in async-nats 0.48 defaults to no_wait:true which returns
+                // immediately when the queue is empty, so we avoid it here.
+                let mut messages = match consumer.messages().await {
                     Ok(m) => m,
                     Err(e) => {
-                        tracing::error!("NATS fetch failed: {e}");
+                        tracing::error!("NATS messages() failed: {e}");
                         let _ = tx.send(Err(DomainError::Internal(e.to_string()))).await;
                         return;
                     }