chore: fix recompense categorie

backend/gestion/db/db_product.go

@@ -143,6 +143,27 @@ func (d *Database) GetProductNamesByIDs(ids []int) (map[int]string, error) {
 	return result, nil
 }
 
+// GetProductCategoriesByIDs retourne un map id→category pour une liste d'IDs.
+func (d *Database) GetProductCategoriesByIDs(ids []int) (map[int]string, error) {
+	result := make(map[int]string, len(ids))
+	if len(ids) == 0 {
+		return result, nil
+	}
+	rows, err := d.GDB.Raw(`SELECT id, category FROM products WHERE id IN ?`, ids).Rows()
+	if err != nil {
+		return result, err
+	}
+	defer rows.Close()
+	for rows.Next() {
+		var id int
+		var category string
+		if err := rows.Scan(&id, &category); err == nil {
+			result[id] = category
+		}
+	}
+	return result, nil
+}
+
 func (d *Database) GetAllProducts() ([]models.Product, error) {
 	log.Println("📦 [GetAllProducts] START")