chore: add quantity stat

backend/gestion/models/stats.go

@@ -28,6 +28,16 @@ type HourRow struct {
 	Revenue float64 `gorm:"column:revenue"`
 }
 
+type QuantityBreakdownRow struct {
+	ProductID     int     `gorm:"column:product_id"`
+	ProductName   string  `gorm:"column:product_name"`
+	Quantity      float64 `gorm:"column:quantity"`
+	OrderCount    int     `gorm:"column:order_count"`
+	TotalSold     float64 `gorm:"column:total_sold"`
+	Revenue       float64 `gorm:"column:revenue"`
+	CategoryColor string  `gorm:"column:category_color"`
+}
+
 type DayRevenueRow struct {
 	Day     time.Time `gorm:"column:day"`
 	Revenue float64   `gorm:"column:revenue"`