Doctrine recipe

Kaly owns no persistence concept: use Doctrine directly. The one rule is the Persistence lifecycle: never share an EntityManager. Inject a shared factory and open a fresh manager per operation:

final class DoctrineEntityManagerFactory
{
    public function __construct(private EntityManagerFactoryConfig $config) {}

    /**
     * @template T
     * @param callable(EntityManager): T $operation
     * @return T
     */
    public function with(callable $operation): mixed
    {
        $em = $this->create();
        try {
            return $operation($em);
        } finally {
            $em->close();
        }
    }
}

Transactions stay explicit, inside the operation — never automatic at the end of a response:

$factory->with(static function (EntityManager $em) use ($order): void {
    $em->transactional(static function () use ($em, $order): void {
        // ...
    });
});

After a failed transaction, discard the manager and open a clean one, even inside the same request. The owner opens, the owner closes. See DI.