feat(composant) : create composant slot tables and migrate data from structure JSON

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/Entity/Product.php

@@ -106,6 +106,12 @@ class Product
     #[ORM\OneToMany(mappedBy: 'product', targetEntity: Composant::class)]
     private Collection $composants;
 
+    /**
+     * @var Collection<int, Piece>
+     */
+    #[ORM\ManyToMany(targetEntity: Piece::class, mappedBy: 'products')]
+    private Collection $linkedPieces;
+
     /**
      * @var Collection<int, MachineProductLink>
      */
@@ -129,6 +135,7 @@ class Product
         $this->customFieldValues = new ArrayCollection();
         $this->pieces            = new ArrayCollection();
         $this->composants        = new ArrayCollection();
+        $this->linkedPieces      = new ArrayCollection();
         $this->machineLinks      = new ArrayCollection();
     }
 
@@ -219,4 +226,12 @@ class Product
     {
         return $this->customFieldValues;
     }
+
+    /**
+     * @return Collection<int, Piece>
+     */
+    public function getLinkedPieces(): Collection
+    {
+        return $this->linkedPieces;
+    }
 }