feat(security) : add role hierarchy for client portal

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

config/packages/security.yaml

@@ -1,4 +1,7 @@
 security:
+    role_hierarchy:
+        ROLE_ADMIN: [ROLE_USER, ROLE_CLIENT]
+
     # https://symfony.com/doc/current/security.html#registering-the-user-hashing-passwords
     password_hashers:
         Symfony\Component\Security\Core\User\PasswordAuthenticatedUserInterface: 'auto'