fix(nats): delete old push consumer before creating pull consumer

crates/adapters/nats/src/lib.rs

@@ -113,6 +113,17 @@ impl MessageSource for NatsMessageSource {
                 }
             };
 
+            // Delete any existing push consumer with this name — can't reuse as pull.
+            // No-op if it doesn't exist or is already a pull consumer.
+            if let Ok(info) = stream.consumer_info(CONSUMER_NAME).await {
+                if info.config.deliver_subject.is_some() {
+                    tracing::info!(
+                        "deleting old push consumer '{CONSUMER_NAME}', replacing with pull"
+                    );
+                    let _ = stream.delete_consumer(CONSUMER_NAME).await;
+                }
+            }
+
             let consumer = match stream
                 .get_or_create_consumer(
                     CONSUMER_NAME,