test: skip scheduled-message E2E tests when NATS server < 2.12

The CI nats-server is older than 2.12.0 and does not support ADR-51
message scheduling. Add a @beforeeach assumeTrue guard that skips both
scheduledMessageIsDeliveredAfterDelay and its reactive counterpart when
NatsProvisioner reports scheduling is unavailable, matching the intent
already documented in the class Javadoc.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: sonus21

rqueue-spring-boot-starter/src/test/java/com/github/sonus21/rqueue/spring/boot/integration/NatsScheduledMessageE2EIT.java

@@ -10,16 +10,19 @@
 package com.github.sonus21.rqueue.spring.boot.integration;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assumptions.assumeTrue;
 
 import com.github.sonus21.rqueue.annotation.RqueueListener;
 import com.github.sonus21.rqueue.core.ReactiveRqueueMessageEnqueuer;
 import com.github.sonus21.rqueue.core.RqueueMessageEnqueuer;
+import com.github.sonus21.rqueue.nats.internal.NatsProvisioner;
 import java.time.Duration;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.TimeUnit;
+import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Tag;
 import org.junit.jupiter.api.Test;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -50,6 +53,9 @@ class NatsScheduledMessageE2EIT extends AbstractNatsBootIT {
   static final Duration NOT_YET_GUARD = Duration.ofMillis(800);
   static final Duration TOTAL_WAIT = Duration.ofSeconds(12);
 
+  @Autowired
+  NatsProvisioner natsProvisioner;
+
   @Autowired
   RqueueMessageEnqueuer enqueuer;
 
@@ -59,6 +65,14 @@ class NatsScheduledMessageE2EIT extends AbstractNatsBootIT {
   @Autowired
   ScheduledListener listener;
 
+  @BeforeEach
+  void requireSchedulingSupport() {
+    assumeTrue(
+        natsProvisioner.isMessageSchedulingSupported(),
+        "Skipping: connected NATS server is older than " + NatsProvisioner.SCHEDULING_MIN_VERSION
+            + " and does not support ADR-51 message scheduling");
+  }
+
   @Test
   void scheduledMessageIsDeliveredAfterDelay() throws Exception {
     enqueuer.enqueueIn("sched-e2e", "delayed-payload", DELAY);