feat(BE): integrate FIFO service for stock adjustments and transfers

- Added FIFO service integration in the adjustments module to manage stockable and usable items for adjustments.
- Created a new repository for adjustment stocks to handle database operations.
- Enhanced the adjustment service to track stock adjustments using FIFO logic for both increase and decrease operations.
- Updated product warehouse DTOs and repositories to include project flock information.
- Implemented FIFO logic in the transfer module to manage stock transfers between warehouses.
- Added integration tests for FIFO operations in stock transfers, ensuring correct stock consumption and replenishment.

internal/entities/adjustment_stock.go

@@ -0,0 +1,29 @@
+package entities
+
+import "time"
+
+// AdjustmentStock tracks FIFO allocation for stock adjustments
+// - For INCREASE adjustments (Stockable): Tracks stock added to warehouse
+// - For DECREASE adjustments (Usable): Tracks stock consumed from warehouse
+type AdjustmentStock struct {
+	Id                 uint   `gorm:"primaryKey"`
+	StockLogId         uint   `gorm:"column:stock_log_id;not null;index"`
+	ProductWarehouseId uint   `gorm:"column:product_warehouse_id;not null"`
+
+	// === FIFO FIELDS FOR INCREASE ADJUSTMENT (Stockable) ===
+	// Tracks stock added to warehouse via adjustment INCREASE
+	TotalQty  float64 `gorm:"column:total_qty;default:0"`  // Total lot quantity available
+	TotalUsed float64 `gorm:"column:total_used;default:0"` // Quantity already used from this lot
+
+	// === FIFO FIELDS FOR DECREASE ADJUSTMENT (Usable) ===
+	// Tracks stock consumed from warehouse via adjustment DECREASE
+	UsageQty   float64 `gorm:"column:usage_qty;default:0"`   // Actual quantity consumed
+	PendingQty float64 `gorm:"column:pending_qty;default:0"` // Pending quantity (waiting for stock)
+
+	CreatedAt time.Time `gorm:"column:created_at;autoCreateTime"`
+	UpdatedAt time.Time `gorm:"column:updated_at;autoUpdateTime"`
+
+	// Relations
+	StockLog         *StockLog         `gorm:"foreignKey:StockLogId;references:Id"`
+	ProductWarehouse *ProductWarehouse `gorm:"foreignKey:ProductWarehouseId;references:Id"`
+}