feat(BE-47,48,49,50): implement inventory adjustment system

- Extend DB schema with product_warehouses and stock_logs tables
- Implement stock adjustment API (increase/decrease operations)
- Add comprehensive validation for all adjustment operations
- Implement audit log system for each adjustment with history tracking
- Include transaction handling, DTOs, seeders, and proper error handling
- Add adjustment history API with pagination and filtering

TODO: Integration testing pending

internal/database/seed/seeder.go

@@ -74,6 +74,10 @@ func Run(db *gorm.DB) error {
 			return err
 		}
 
+		if err := seedProductWarehouse(tx, adminID); err != nil {
+			return err
+		}
+
 		fmt.Println("✅ Master data seeding completed")
 		return nil
 	})
@@ -675,10 +679,6 @@ func seedNonstocks(tx *gorm.DB, createdBy uint, uoms map[string]uint, suppliers
 }
 
 // nanti saya isi
-func seedProductWarehouse(tx *gorm.DB, createdBy uint, products map[string]uint, warehouses map[string]uint) error {
-
-	return nil
-}
 
 func seedFlags(tx *gorm.DB, flagableID uint, flagableType string, flags []utils.FlagType) error {
 	if len(flags) == 0 {
@@ -766,6 +766,39 @@ func seedBanks(tx *gorm.DB, createdBy uint) error {
 	return nil
 }
 
+func seedProductWarehouse(tx *gorm.DB, createdBy uint) error {
+
+	seeds := []struct {
+		ProductID   uint
+		WarehouseID uint
+		Quantity    float64
+	}{
+		{ProductID: 1, WarehouseID: 1, Quantity: 100},
+		{ProductID: 2, WarehouseID: 2, Quantity: 200},
+		{ProductID: 1, WarehouseID: 1, Quantity: 300},
+	}
+
+	for _, seed := range seeds {
+		var productWarehouse entity.ProductWarehouse
+		err := tx.Where("product_id = ? AND warehouse_id = ?", seed.ProductID, seed.WarehouseID).First(&productWarehouse).Error
+		if errors.Is(err, gorm.ErrRecordNotFound) {
+			productWarehouse = entity.ProductWarehouse{
+				ProductId:   seed.ProductID,
+				WarehouseId: seed.WarehouseID,
+				Quantity:    seed.Quantity,
+				CreatedBy:   createdBy,
+			}
+			if err := tx.Create(&productWarehouse).Error; err != nil {
+				return err
+			}
+		} else if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
 func ptr[T any](v T) *T {
 	return &v
 }