fix(events): suppress stream poll loop in test profile

CDI fires StartupEvent to all observer beans regardless of @InjectMock
substitution, causing GameCreationStreamClient and GameCreationStreamListener
to start their poll loops during @QuarkusTest even when mocked. Without
Redis configured in account tests, this floods logs with NPE stack traces
from the unconfigured RedisDataSource synthetic bean.

- Switch @Startup/@PostConstruct to @Observes StartupEvent on both beans
- Guard startup body with nowchess.game-creation-stream.enabled (default true)
- Disable the flag in modules/account/src/test/resources/application.yml

Mirrors the nowchess.coordinator.enabled pattern in InstanceHeartbeatService.

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

modules/core/src/main/scala/de/nowchess/chess/redis/GameCreationStreamListener.scala

@@ -7,10 +7,11 @@ import de.nowchess.chess.config.RedisConfig
 import de.nowchess.chess.service.GameCreationService
 import io.quarkus.redis.datasource.RedisDataSource
 import io.quarkus.redis.datasource.stream.{StreamMessage, XAddArgs, XGroupCreateArgs, XReadGroupArgs}
-import io.quarkus.runtime.Startup
-import jakarta.annotation.PostConstruct
+import io.quarkus.runtime.StartupEvent
 import jakarta.enterprise.context.ApplicationScoped
+import jakarta.enterprise.event.Observes
 import jakarta.inject.Inject
+import org.eclipse.microprofile.config.inject.ConfigProperty
 import org.eclipse.microprofile.context.ManagedExecutor
 import org.jboss.logging.Logger
 import scala.compiletime.uninitialized
@@ -19,7 +20,6 @@ import scala.util.{Failure, Success, Try}
 import java.time.Duration
 import java.util.UUID
 
-@Startup
 @ApplicationScoped
 class GameCreationStreamListener:
 
@@ -29,6 +29,8 @@ class GameCreationStreamListener:
   @Inject var creationService: GameCreationService = uninitialized
   @Inject var executor: ManagedExecutor            = uninitialized
   @Inject var redisConfig: RedisConfig             = uninitialized
+  @ConfigProperty(name = "nowchess.game-creation-stream.enabled", defaultValue = "true")
+  private var streamEnabled: Boolean = true
   // scalafix:on DisableSyntax.var
 
   private val log          = Logger.getLogger(classOf[GameCreationStreamListener])
@@ -41,14 +43,14 @@ class GameCreationStreamListener:
   private def responseStream: String = s"${redisConfig.prefix}:game-creation-response"
   private def dlqStream: String      = s"${redisConfig.prefix}:dlq"
 
-  @PostConstruct
-  def start(): Unit =
-    createGroupIfAbsent()
-    executor.submit(
-      new Runnable:
-        def run(): Unit = pollLoop(),
-    )
-    log.infof("Game-creation request listener started (consumer=%s)", consumerId)
+  def start(@Observes _ev: StartupEvent): Unit =
+    if streamEnabled then
+      createGroupIfAbsent()
+      executor.submit(
+        new Runnable:
+          def run(): Unit = pollLoop(),
+      )
+      log.infof("Game-creation request listener started (consumer=%s)", consumerId)
 
   private def createGroupIfAbsent(): Unit =
     Try(