Enable native lazy objects for PHP 8.4+ (#25)

* Enable native lazy objects for PHP 8.4+

Use new non-deprecated Doctrine ORM API on PHP 8.4+ with Doctrine ORM 3.5+:
- Replace `ORMSetup::createAttributeMetadataConfiguration()` with `createAttributeMetadataConfig()`
- Enable native lazy objects via `$config->enableNativeLazyObjects(true)`

Falls back to the old API on older PHP/Doctrine versions for backward compatibility.

This addresses the following deprecations on PHP 8.4+:
- Doctrine\ORM\ORMSetup::createAttributeMetadataConfiguration is deprecated
- ProxyHelper::generateLazyGhost() is deprecated
- Symfony\Component\VarExporter\LazyGhostTrait is deprecated

* Fix native lazy objects compatibility and update test fixtures

- Add $number property to TestEntityWithId to ensure entities are never
  empty (prevents PHP 8.4 from skipping proxy creation for id-only entities)
- Update EntityPreloader to check isUninitializedObject before getValue
  to prevent accidental lazy initialization
- Update expected SQL queries in EntityPreloadSyntheticTest to account
  for the new number column
- Add PHPStan ignore rules for test fixtures

* Enable native lazy objects for PHP 8.4+

Re-enable the native lazy objects feature now that tests have been
updated with the $number column to ensure entities are never empty.

* revert useless change

* x

Author: JanTvrdik