fix(custom-fields) : empêche EntityNotFoundException sur CustomField orphelin

Même pattern que la fix Piece (003e419) : helper ensureCustomFieldExists()
qui force l'init du proxy lazy et catch EntityNotFoundException dans
MachineStructureController::normalizeCustomFieldValues() et
CustomFieldValueController::normalizeCustomFieldValue(). Les CFV pointant
vers un CustomField supprimé sont silencieusement skippés au lieu de
crasher la vue machine entière.

src/Controller/MachineStructureController.php

@@ -832,6 +832,25 @@ class MachineStructureController extends AbstractController
         }
     }
 
+    /**
+     * Same defensive pattern as ensurePieceExists() but for CustomField.
+     * A CustomFieldValue may carry a stale FK to a deleted CustomField; touching
+     * the lazy proxy raises EntityNotFoundException and 500s the machine view.
+     */
+    private function ensureCustomFieldExists(?CustomField $cf): ?CustomField
+    {
+        if (null === $cf) {
+            return null;
+        }
+        try {
+            $cf->getId();
+
+            return $cf;
+        } catch (EntityNotFoundException) {
+            return null;
+        }
+    }
+
     private function normalizePiece(Piece $piece): array
     {
         $type = $piece->getTypePiece();
@@ -942,7 +961,10 @@ class MachineStructureController extends AbstractController
             if (!$cfv instanceof CustomFieldValue) {
                 continue;
             }
-            $cf      = $cfv->getCustomField();
+            $cf = $this->ensureCustomFieldExists($cfv->getCustomField());
+            if (null === $cf) {
+                continue;
+            }
             $items[] = [
                 'id'          => $cfv->getId(),
                 'value'       => $cfv->getValue(),