fix: use dedicated rabbitmq user for CI service container

.github/workflows/nuget_release.yml

@@ -37,10 +37,14 @@ jobs:
           --health-timeout=5s
           --health-retries=5
       rabbitmq:
-        image: rabbitmq:3
+        # Default 'guest' user is restricted to localhost in RabbitMQ.
+        # GitHub Actions service containers route through port forwarding,
+        # so the broker sees connections as non-localhost and rejects
+        # 'guest'. Override with a dedicated test user.
+        image: rabbitmq:4-management
         env:
-          RABBITMQ_DEFAULT_USER: guest
-          RABBITMQ_DEFAULT_PASS: guest
+          RABBITMQ_DEFAULT_USER: trax
+          RABBITMQ_DEFAULT_PASS: trax123
         ports:
           - 5672:5672
         options: >-

.github/workflows/pull_request.yml

@@ -26,10 +26,14 @@ jobs:
           --health-timeout=5s
           --health-retries=5
       rabbitmq:
-        image: rabbitmq:3
+        # Default 'guest' user is restricted to localhost in RabbitMQ.
+        # GitHub Actions service containers route through port forwarding,
+        # so the broker sees connections as non-localhost and rejects
+        # 'guest'. Override with a dedicated test user.
+        image: rabbitmq:4-management
         env:
-          RABBITMQ_DEFAULT_USER: guest
-          RABBITMQ_DEFAULT_PASS: guest
+          RABBITMQ_DEFAULT_USER: trax
+          RABBITMQ_DEFAULT_PASS: trax123
         ports:
           - 5672:5672
         options: >-

tests/Trax.Effect.Tests.Broadcaster/UnitTests/BroadcasterRegistrationTests.cs

@@ -75,7 +75,7 @@ public void UseRabbitMq_RegistersOptions()
         var builder = new TraxBuilder(services, registry);
 
         builder.AddEffects(effects =>
-            effects.UseBroadcaster(b => b.UseRabbitMq("amqp://guest:guest@localhost:5672"))
+            effects.UseBroadcaster(b => b.UseRabbitMq("amqp://trax:trax123@localhost:5672"))
         );
 
         services.Should().Contain(sd => sd.ServiceType == typeof(RabbitMqBroadcasterOptions));

tests/Trax.Effect.Tests.Broadcaster/UnitTests/RabbitMqBroadcasterIntegrationTests.cs

@@ -9,13 +9,16 @@ namespace Trax.Effect.Tests.Broadcaster.UnitTests;
 /// <summary>
 /// Integration tests that exercise <see cref="RabbitMqTrainEventBroadcaster"/> and
 /// <see cref="RabbitMqTrainEventReceiver"/> against a real RabbitMQ broker.
-/// CI provisions a rabbitmq:3 service container; locally a developer-mode broker
-/// listens on amqp://guest:guest@localhost:5672/.
+/// CI provisions a rabbitmq:4-management service container with a dedicated
+/// 'trax' user (default 'guest' is restricted to localhost in RabbitMQ, and CI
+/// service containers route through port forwarding so the broker sees
+/// non-localhost connections). The Trax.Samples docker-compose broker is
+/// configured the same way for local parity.
 /// </summary>
 [TestFixture]
 public class RabbitMqBroadcasterIntegrationTests
 {
-    private const string AmqpUri = "amqp://guest:guest@localhost:5672/";
+    private const string AmqpUri = "amqp://trax:trax123@localhost:5672/";
 
     private static RabbitMqBroadcasterOptions Options(string suffix) =>
         new()