feat: group order items by product with category totals

backend/gestion/db/db_command_items.go

@@ -211,6 +211,7 @@ func (d *Database) GetCommandItems(commandID int) ([]map[string]any, error) {
 		LivreurAssign     *string    `gorm:"column:livreur_assign"`
 		CommandCreatedAt  *time.Time `gorm:"column:command_created_at"`
 		Category          string     `gorm:"column:category"`
+		Unit              string     `gorm:"column:unit"`
 		ClientOrderNumber int        `gorm:"column:client_order_number"`
 	}
 
@@ -236,7 +237,8 @@ func (d *Database) GetCommandItems(commandID int) ([]map[string]any, error) {
 		c.referral_used,
 		c.livreur_assign,
 		c.created_at as command_created_at,
-		p.category,
+		COALESCE(p.category, '') as category,
+		COALESCE(p.unit, '') as unit,
 		c.client_order_id as client_order_number
 	FROM command_items ci
 	LEFT JOIN commandes c ON ci.command_id = c.id
@@ -283,6 +285,7 @@ func (d *Database) GetCommandItems(commandID int) ([]map[string]any, error) {
 			"livreur_assign":      ptrStr(row.LivreurAssign),
 			"command_created_at":  commandCreatedAt,
 			"category":            row.Category,
+			"unit":                row.Unit,
 			"client_order_number": row.ClientOrderNumber,
 		}
 		items = append(items, item)