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/modules/inventory/adjustments/dto/adjustment.dto.go

@@ -9,56 +9,123 @@ import (
 
 // === DTO Structs ===
 
+type ProductBaseDTO struct {
+	Id   uint   `json:"id"`
+	Name string `json:"name"`
+	SKU  string `json:"sku"`
+}
+
+type WarehouseBaseDTO struct {
+	Id   uint   `json:"id"`
+	Name string `json:"name"`
+}
+
+type ProductWarehouseDTO struct {
+	Id          uint              `json:"id"`
+	ProductId   uint              `json:"product_id"`
+	WarehouseId uint              `json:"warehouse_id"`
+	Quantity    float64           `json:"quantity"`
+	Product     *ProductBaseDTO   `json:"product,omitempty"`
+	Warehouse   *WarehouseBaseDTO `json:"warehouse,omitempty"`
+}
+
 type AdjustmentBaseDTO struct {
-	Id        uint      `json:"id"`
-	Name      string    `json:"name"`
+	Id                 uint                 `json:"id"`
+	TransactionType    string               `json:"transaction_type"`
+	Quantity           float64              `json:"quantity"`
+	BeforeQuantity     float64              `json:"before_quantity"`
+	AfterQuantity      float64              `json:"after_quantity"`
+	Note               string               `json:"note,omitempty"`
+	ProductWarehouseId uint                 `json:"product_warehouse_id"`
+	ProductWarehouse   *ProductWarehouseDTO `json:"product_warehouse,omitempty"`
 }
 
 type AdjustmentListDTO struct {
 	AdjustmentBaseDTO
-	CreatedUser *userDTO.UserBaseDTO `json:"created_user"`
-	CreatedAt time.Time `json:"created_at"`
-	UpdatedAt time.Time `json:"updated_at"`
+	CreatedUser *userDTO.UserBaseDTO `json:"created_user,omitempty"`
+	CreatedAt   time.Time            `json:"created_at"`
 }
 
 type AdjustmentDetailDTO struct {
 	AdjustmentListDTO
+	UpdatedAt time.Time `json:"updated_at"`
 }
 
 // === Mapper Functions ===
 
-func ToAdjustmentBaseDTO(e entity.Adjustment) AdjustmentBaseDTO {
-	return AdjustmentBaseDTO{
-		Id:    e.Id,
-		Name:  e.Name,
+func ToProductBaseDTO(e *entity.Product) *ProductBaseDTO {
+	if e == nil {
+		return nil
+	}
+	sku := ""
+	if e.Sku != nil {
+		sku = *e.Sku
+	}
+	return &ProductBaseDTO{
+		Id:   e.Id,
+		Name: e.Name,
+		SKU:  sku,
 	}
 }
 
-func ToAdjustmentListDTO(e entity.Adjustment) AdjustmentListDTO {
+func ToWarehouseBaseDTO(e *entity.Warehouse) *WarehouseBaseDTO {
+	if e == nil {
+		return nil
+	}
+	return &WarehouseBaseDTO{
+		Id:   e.Id,
+		Name: e.Name,
+	}
+}
+
+func ToProductWarehouseDTO(e *entity.ProductWarehouse) *ProductWarehouseDTO {
+	if e == nil {
+		return nil
+	}
+	return &ProductWarehouseDTO{
+		Id:          e.Id,
+		ProductId:   e.ProductId,
+		WarehouseId: e.WarehouseId,
+		Quantity:    e.Quantity,
+		Product:     ToProductBaseDTO(&e.Product),
+		Warehouse:   ToWarehouseBaseDTO(&e.Warehouse),
+	}
+}
+
+func ToAdjustmentBaseDTO(e *entity.StockLog) AdjustmentBaseDTO {
+	return AdjustmentBaseDTO{
+		Id:                 e.Id,
+		TransactionType:    e.TransactionType,
+		Quantity:           e.Quantity,
+		BeforeQuantity:     e.BeforeQuantity,
+		AfterQuantity:      e.AfterQuantity,
+		Note:               e.Note,
+		ProductWarehouseId: e.ProductWarehouseId,
+		ProductWarehouse:   ToProductWarehouseDTO(e.ProductWarehouse),
+	}
+}
+
+func ToAdjustmentListDTO(e *entity.StockLog) AdjustmentListDTO {
 	var createdUser *userDTO.UserBaseDTO
-	if e.CreatedUser.Id != 0 {
-		mapped := userDTO.ToUserBaseDTO(e.CreatedUser)
-		createdUser = &mapped
+	if e.CreatedUser != nil {
+		createdUser = &userDTO.UserBaseDTO{
+			Id:     e.CreatedUser.Id,
+			IdUser: e.CreatedUser.IdUser,
+			Email:  e.CreatedUser.Email,
+			Name:   e.CreatedUser.Name,
+		}
 	}
 
 	return AdjustmentListDTO{
 		AdjustmentBaseDTO: ToAdjustmentBaseDTO(e),
-		CreatedAt:   e.CreatedAt,
-		UpdatedAt:   e.UpdatedAt,
-		CreatedUser: createdUser,
+		CreatedUser:       createdUser,
+		CreatedAt:         e.CreatedAt,
 	}
 }
 
-func ToAdjustmentListDTOs(e []entity.Adjustment) []AdjustmentListDTO {
-	result := make([]AdjustmentListDTO, len(e))
-	for i, r := range e {
-		result[i] = ToAdjustmentListDTO(r)
-	}
-	return result
-}
-
-func ToAdjustmentDetailDTO(e entity.Adjustment) AdjustmentDetailDTO {
+func ToAdjustmentDetailDTO(e *entity.StockLog) AdjustmentDetailDTO {
 	return AdjustmentDetailDTO{
 		AdjustmentListDTO: ToAdjustmentListDTO(e),
+		UpdatedAt:         e.UpdatedAt,
 	}
 }