feat: Integrate UserManager and HibernateUserManager in session management

knockoutwhistweb/app/modules/GatewayModule.scala

@@ -1,10 +1,24 @@
 package modules
 
 import com.google.inject.AbstractModule
+import di.EntityManagerProvider
+import jakarta.persistence.EntityManager
 import logic.Gateway
+import logic.user.UserManager
+import logic.user.impl.HibernateUserManager
 
 class GatewayModule extends AbstractModule {
   override def configure(): Unit = {
     bind(classOf[Gateway]).asEagerSingleton()
+
+    // Bind HibernateUserManager for production (when GatewayModule is used)
+    bind(classOf[UserManager])
+      .to(classOf[HibernateUserManager])
+      .asEagerSingleton()
+
+    // Bind EntityManager for JPA
+    bind(classOf[EntityManager])
+      .toProvider(classOf[EntityManagerProvider])
+      .asEagerSingleton()
   }
 }