fix: handle DocumentNotFound for nullable ElasticEntity properties

When resolving a nullable AbstractElasticEntity property and the
referenced document doesn't exist in ES, set the value to null instead
of letting DocumentNotFound propagate and kill the entire parent entity
creation.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: Spamercz

src/Factory/EntityFactory.php

@@ -243,10 +243,19 @@ class: $value[\Spameri\Elastic\Model\Insert\PrepareEntityArray::ENTITY_CLASS],
 						$this->identityMap->uninitializedEntityList[$propertyTypeName][$value][$property->getName()][$hit->id()] = $class;
 
 					} else {
-						$propertyValue = $entityManager->find(
-							id: $value,
-							class: $propertyTypeName,
-						);
+						try {
+							$propertyValue = $entityManager->find(
+								id: $value,
+								class: $propertyTypeName,
+							);
+						} catch (\Spameri\Elastic\Exception\DocumentNotFound $e) {
+							if ($reflectionPropertyType->allowsNull()) {
+								$propertyValue = null;
+								$setNull = true;
+							} else {
+								throw $e;
+							}
+						}
 					}
 
 				} elseif ($this->container->getByType($propertyTypeName, false) !== null) {