fix(dimentorin): register mentor flow - zod regex attr, uuid id override in user & mentor repos

- Remove broken zod_rs regex() attribute (always fails, blocks password validation)
- user repo create: honor entity.id instead of silently generating new v4 (broke FK mentor.user_id)
- mentor repo create: set id explicitly (was NULL not-null violation)

imphnen-iam/src/users/infrastructure/persistence/postgres_user_repository.rs

@@ -107,7 +107,9 @@ impl UserRepository for PostgresUserRepository {
 			.ok()
 			.or_else(|| entity.role.id.is_empty().then_some(Uuid::nil()));
 		let active_model = UserActiveModel {
-			id: ActiveValue::Set(Uuid::new_v4()),
+			id: ActiveValue::Set(
+				Uuid::parse_str(&entity.id).unwrap_or_else(|_| Uuid::new_v4()),
+			),
 			email: ActiveValue::Set(entity.email.clone()),
 			password_hash: ActiveValue::Set(entity.password),
 			username: ActiveValue::Set(entity.email.clone()),