fix(tests): corriger 48 tests en echec (mocks, assertions, stubs)

- KeycloakAdminClientImpl[Complete]Test: isConnected utilise tokenManager() et non serverInfo()
- AuditResourceTest: injecter defaultRealm="master" dans @BeforeEach, fix purgeOldLogs (retourne long)
- AuditServiceImplAdditionalTest/CompleteTest: ajouter @InjectMocks + @Mock (NPE auditLogRepository=null)
- RoleServiceImpl: lancer IllegalArgumentException si message contient "not found" ou "404"
- SyncServiceImplTest: syncAllRealms/isKeycloakAvailable utilisent getAllRealms(), corriger assertions sante
- UserServiceImplTest: corriger assertion header CSV (prenom/nom au lieu de firstName/lastName)

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

src/main/java/dev/lions/user/manager/service/impl/RoleServiceImpl.java

@@ -234,6 +234,10 @@ public class RoleServiceImpl implements RoleService {
             return RoleMapper.toDTOList(roleReps, realmName, TypeRole.REALM_ROLE);
         } catch (Exception e) {
             log.error("Erreur lors de la récupération des rôles realm du realm {}: {}", realmName, e.getMessage(), e);
+            String msg = e.getMessage() != null ? e.getMessage().toLowerCase() : "";
+            if (msg.contains("not found") || msg.contains("404")) {
+                throw new IllegalArgumentException("Realm '" + realmName + "' introuvable: " + e.getMessage(), e);
+            }
             throw new RuntimeException("Erreur lors de la récupération des rôles realm: " + e.getMessage(), e);
         }
     }