Add transactional support to CharacterService, ScenarioService, and UserService

- Annotate create, update, and delete methods in CharacterService and ScenarioService with @Transactional to ensure proper transaction management.
- Add @Transactional annotation to the createUser method in UserService for consistency in transaction handling across services.
- Enhance data integrity and consistency during operations involving character, scenario, and user management.

src/main/java/de/neitzel/roleplay/business/CharacterService.java

@@ -7,6 +7,7 @@ import de.neitzel.roleplay.fascade.model.CreateCharacterRequest;
 
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
+import jakarta.transaction.Transactional;
 
 import java.util.List;
 import java.util.Optional;
@@ -54,6 +55,7 @@ public class CharacterService {
      * @param request the create request (name and role required)
      * @return the created character definition
      */
+    @Transactional
     public CharacterDefinition create(final CreateCharacterRequest request) {
         CharacterEntity entity = fromRequest(request, request.getId() != null ? request.getId() : UUID.randomUUID());
         characterRepository.persist(entity);
@@ -68,6 +70,7 @@ public class CharacterService {
      * @return the updated character definition
      * @throws java.util.NoSuchElementException if the character does not exist
      */
+    @Transactional
     public CharacterDefinition update(final UUID id, final CreateCharacterRequest request) {
         CharacterEntity entity = characterRepository.findByIdOptional(id);
         if (entity == null) {
@@ -84,6 +87,7 @@ public class CharacterService {
      * @param id the character UUID
      * @return true if deleted, false if no character existed
      */
+    @Transactional
     public boolean delete(final UUID id) {
         CharacterEntity entity = characterRepository.findByIdOptional(id);
         if (entity == null) {

src/main/java/de/neitzel/roleplay/business/ScenarioService.java

@@ -13,8 +13,8 @@ import de.neitzel.roleplay.fascade.model.ScenarioSummary;
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
 import jakarta.persistence.EntityManager;
+import jakarta.transaction.Transactional;
 
-import java.util.ArrayList;
 import java.util.List;
 import java.util.Optional;
 import java.util.UUID;
@@ -66,6 +66,7 @@ public class ScenarioService {
      * @return the created scenario summary
      * @throws IllegalArgumentException if any referenced character id is not found
      */
+    @Transactional
     public ScenarioSummary create(final CreateScenarioRequest request) {
         UUID scenarioId = UUID.randomUUID();
         ScenarioEntity scenario = new ScenarioEntity();
@@ -104,6 +105,7 @@ public class ScenarioService {
      * @throws java.util.NoSuchElementException if the scenario does not exist
      * @throws IllegalArgumentException        if any referenced character id is not found
      */
+    @Transactional
     public ScenarioSummary update(final UUID id, final CreateScenarioRequest request) {
         ScenarioEntity scenario = scenarioRepository.findByIdWithCharacters(id);
         if (scenario == null) {
@@ -141,6 +143,7 @@ public class ScenarioService {
      * @param id the scenario UUID
      * @return true if deleted, false if no scenario existed
      */
+    @Transactional
     public boolean delete(final UUID id) {
         ScenarioEntity scenario = scenarioRepository.findByIdWithCharacters(id);
         if (scenario == null) {

src/main/java/de/neitzel/roleplay/business/UserService.java

@@ -7,6 +7,7 @@ import de.neitzel.roleplay.data.UserRepository;
 
 import jakarta.enterprise.context.ApplicationScoped;
 import jakarta.inject.Inject;
+import jakarta.transaction.Transactional;
 
 import java.util.List;
 import java.util.stream.Collectors;
@@ -42,6 +43,7 @@ public class UserService {
      * @return the created user summary
      * @throws IllegalArgumentException if username is blank, password is blank, role is invalid, or username already exists
      */
+    @Transactional
     public UserSummary createUser(final CreateUserRequest request) {
         String username = request.getUsername();
         String password = request.getPassword();