chore(nats): poller fetch-wait fix, producer-mode wiring, copyright sweep

- RqueueMessagePoller now forwards the configured pollingInterval to
  MessageBroker.pop instead of Duration.ZERO, letting JetStream long-poll
  rather than spinning $JS.API.CONSUMER.MSG.NEXT requests at full speed.
  Covered by a new test in RqueueMessageListenerContainerBrokerBranchTest.
- RqueueNatsAutoConfig wires RqueueConfig into NatsStreamValidator so
  producer-only deployments skip durable consumer creation.
- StringUtils-based null/empty checks in RqueueNatsAutoConfig.
- Copyright headers normalized to 2026 across the NATS-touched files.

Assisted-By: Claude Code

Author: sonus21

build.gradle

@@ -85,7 +85,7 @@ ext {
 
 subprojects {
     group = "com.github.sonus21"
-    version = "4.0.0-SK3"
+    version = "4.0.0-SK5"
 
     dependencies {
         // https://mvnrepository.com/artifact/org.springframework/spring-messaging

rqueue-core/src/main/java/com/github/sonus21/rqueue/config/NatsBackendCondition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024-2026 Sonu Kumar
+ * Copyright (c) 2026 Sonu Kumar
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * You may not use this file except in compliance with the License.

rqueue-core/src/main/java/com/github/sonus21/rqueue/config/RedisBackendCondition.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024-2026 Sonu Kumar
+ * Copyright (c) 2026 Sonu Kumar
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * You may not use this file except in compliance with the License.

rqueue-core/src/main/java/com/github/sonus21/rqueue/exception/BackendCapabilityException.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024-2026 Sonu Kumar
+ * Copyright (c) 2026 Sonu Kumar
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * You may not use this file except in compliance with the License.

rqueue-core/src/main/java/com/github/sonus21/rqueue/listener/RqueueMessagePoller.java

@@ -61,7 +61,11 @@ abstract class RqueueMessagePoller extends MessageContainerBase {
   private List<RqueueMessage> getMessages(QueueDetail queueDetail, int count) {
     return rqueueBeanProvider
         .getMessageBroker()
-        .pop(queueDetail, queueDetail.resolvedConsumerName(), count, Duration.ZERO);
+        .pop(
+            queueDetail,
+            queueDetail.resolvedConsumerName(),
+            count,
+            Duration.ofMillis(pollingInterval));
   }
 
   private void execute(

rqueue-core/src/main/java/com/github/sonus21/rqueue/metrics/RqueueQueueMetricsProvider.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024-2026 Sonu Kumar
+ * Copyright (c) 2026 Sonu Kumar
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * You may not use this file except in compliance with the License.

rqueue-core/src/main/java/com/github/sonus21/rqueue/repository/MessageBrowsingRepository.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024-2026 Sonu Kumar
+ * Copyright (c) 2026 Sonu Kumar
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * You may not use this file except in compliance with the License.

rqueue-core/src/main/java/com/github/sonus21/rqueue/serdes/RqJacksonSerDes.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024-2026 Sonu Kumar
+ * Copyright (c) 2026 Sonu Kumar
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * You may not use this file except in compliance with the License.

rqueue-core/src/main/java/com/github/sonus21/rqueue/serdes/RqueueSerDes.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024-2026 Sonu Kumar
+ * Copyright (c) 2026 Sonu Kumar
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * You may not use this file except in compliance with the License.

rqueue-core/src/test/java/com/github/sonus21/rqueue/core/impl/ReactiveRqueueMessageEnqueuerBrokerRoutingTest.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2024-2026 Sonu Kumar
+ * Copyright (c) 2026 Sonu Kumar
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * You may not use this file except in compliance with the License.