feat(reference-auto) : add automatic reference generation for pieces

ModelType defines a formula with placeholders ({serie}{diametre}{type}).
ReferenceAutoGenerator resolves it from CustomFieldValues with trim+uppercase normalisation.
ReferenceAutoSubscriber (onFlush) recalculates on Piece/CFV insert/update/delete.

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

src/EventSubscriber/ReferenceAutoSubscriber.php

@@ -0,0 +1,77 @@
+<?php
+
+declare(strict_types=1);
+
+namespace App\EventSubscriber;
+
+use App\Entity\CustomFieldValue;
+use App\Entity\Piece;
+use App\Service\ReferenceAutoGenerator;
+use Doctrine\Bundle\DoctrineBundle\Attribute\AsDoctrineListener;
+use Doctrine\ORM\Event\OnFlushEventArgs;
+use Doctrine\ORM\Events;
+
+#[AsDoctrineListener(event: Events::onFlush)]
+final class ReferenceAutoSubscriber
+{
+    public function __construct(private readonly ReferenceAutoGenerator $generator) {}
+
+    public function onFlush(OnFlushEventArgs $args): void
+    {
+        $em  = $args->getObjectManager();
+        $uow = $em->getUnitOfWork();
+
+        $piecesToRecalculate = [];
+
+        foreach ($uow->getScheduledEntityInsertions() as $entity) {
+            if ($entity instanceof Piece) {
+                $piecesToRecalculate[$entity->getId()] = $entity;
+            }
+        }
+
+        foreach ($uow->getScheduledEntityUpdates() as $entity) {
+            if ($entity instanceof Piece) {
+                $piecesToRecalculate[$entity->getId()] = $entity;
+            }
+        }
+
+        // For CFV insertions: the new CFV is not yet in the DB, so Piece's lazy-loaded
+        // collection won't contain it. We must add it manually so the generator sees it.
+        foreach ($uow->getScheduledEntityInsertions() as $entity) {
+            if ($entity instanceof CustomFieldValue && $entity->getPiece()) {
+                $piece = $entity->getPiece();
+                if (!$piece->getCustomFieldValues()->contains($entity)) {
+                    $piece->getCustomFieldValues()->add($entity);
+                }
+                $piecesToRecalculate[$piece->getId()] = $piece;
+            }
+        }
+
+        foreach ($uow->getScheduledEntityUpdates() as $entity) {
+            if ($entity instanceof CustomFieldValue && $entity->getPiece()) {
+                $piece                                = $entity->getPiece();
+                $piecesToRecalculate[$piece->getId()] = $piece;
+            }
+        }
+
+        // For CFV deletions: remove from collection so the generator doesn't see stale values.
+        foreach ($uow->getScheduledEntityDeletions() as $entity) {
+            if ($entity instanceof CustomFieldValue && $entity->getPiece()) {
+                $piece = $entity->getPiece();
+                $piece->getCustomFieldValues()->removeElement($entity);
+                $piecesToRecalculate[$piece->getId()] = $piece;
+            }
+        }
+
+        $meta = $em->getClassMetadata(Piece::class);
+
+        foreach ($piecesToRecalculate as $piece) {
+            $newRef = $this->generator->generate($piece);
+
+            if ($piece->getReferenceAuto() !== $newRef) {
+                $piece->setReferenceAuto($newRef);
+                $uow->recomputeSingleEntityChangeSet($meta, $piece);
+            }
+        }
+    }
+}