fix(db): remove the seeded test user from all environments

V1 inserted test@example.com / password123 everywhere, including prod. V5 deletes that row only when email and seed hash both match.

src/main/resources/db/migration/V5__Remove_Seeded_Test_User.sql

@@ -0,0 +1,5 @@
+-- V1 seeded test@example.com with the password 'password123' into every environment.
+-- The hash check makes sure only that seed row goes; user_settings follows via ON DELETE CASCADE.
+DELETE FROM users
+WHERE email = 'test@example.com'
+  AND password = '$2a$10$3FApyf15qVEvFLEvl/d7aecSMZlslQdXiYlDgbOa4DfGWu4l0VCY.';

src/test/java/auth_service/modules/user/persistence/UserRepositoryTest.java

@@ -145,4 +145,10 @@ class UserRepositoryTest extends AbstractPersistenceTest {
 
         assertThrows(UserNotFoundException.class, () -> userRepository.updateSettings(-1L, null, settings));
     }
+
+    @Test
+    void migrations_LeaveNoSeededTestUser() {
+        // V1 seeded test@example.com with a known password; it must not exist after all migrations.
+        assertTrue(userRepository.findByEmail("test@example.com").isEmpty());
+    }
 }