feat(backend): 出入库搜索重构 + 商品编码搜索 + KPI/确认售价/详细搜索

- 搜索 keyword 命中改为 单号/酒名(名+拼音)/商品编码，去掉往来单位匹配
- applyStockOrderDetailFilters 合并明细过滤为单条子查询（同一明细语义）+ 新增 product_code
- 新增出入库 KPI summary、出库确认售价(confirm-sale) 及路由
- 补充/更新对应单元测试

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/internal/service/stock.go

@@ -163,6 +163,12 @@ type CostConfirmItem struct {
 	UnitPrice float64 `json:"unit_price"`
 }
 
+// SaleConfirmItem 出库「确认售价」的一条明细（先出后定价）。
+type SaleConfirmItem struct {
+	ItemID    uint64  `json:"item_id"`
+	SalePrice float64 `json:"sale_price"`
+}
+
 // ConfirmStockInCost 「确认进价」：调货等场景以 0 价（暂估）入库并已审核/已出库后，
 // 价格确定时补填真实进价。不反审核、不撤销任何已发生的动作，而是在一个事务内
 // 前向写补偿：
@@ -262,6 +268,63 @@ func (s *StockService) ConfirmStockInCost(shopID, orderID, userID uint64, role s
 	})
 }
 
+// ConfirmStockOutSale 出库「先出后定价」：对 sale_price<=0 的明细写真实售价，
+// 重算应收(total_amount=Σ售价×数量)并补应收差额流水。仅 admin/superadmin、已审核单可确认。
+func (s *StockService) ConfirmStockOutSale(shopID, orderID, userID uint64, role string, items []SaleConfirmItem) error {
+	if role != "admin" && role != "superadmin" {
+		return ErrForbidden
+	}
+	return s.db.Transaction(func(tx *gorm.DB) error {
+		var order model.StockOutOrder
+		if err := tx.Preload("Items").Where("id = ? AND shop_id = ?", orderID, shopID).
+			First(&order).Error; err != nil {
+			return err
+		}
+		if order.Status != "approved" {
+			return errors.New("只有已审核单据可确认售价")
+		}
+
+		want := make(map[uint64]float64, len(items))
+		for _, it := range items {
+			want[it.ItemID] = it.SalePrice
+		}
+
+		now := time.Now()
+		var totalDiff float64
+		for i := range order.Items {
+			it := &order.Items[i]
+			newPrice, ok := want[it.ID]
+			if !ok || newPrice == it.SalePrice {
+				continue
+			}
+			diff := (newPrice - it.SalePrice) * it.Quantity
+			totalDiff += diff
+			if err := tx.Model(it).Update("sale_price", newPrice).Error; err != nil {
+				return err
+			}
+		}
+
+		if totalDiff == 0 {
+			return nil
+		}
+
+		// 应收总额按差额重算
+		if err := tx.Model(&order).
+			Update("total_amount", gorm.Expr("total_amount + ?", totalDiff)).Error; err != nil {
+			return err
+		}
+
+		// 应收差额调整流水（滚动余额，与出库审核建应收同口径 last+amount）
+		bal := partnerLastBalance(tx, shopID, order.PartnerID) + totalDiff
+		oid := order.ID
+		return tx.Create(&model.FinanceRecord{
+			ShopID: shopID, PartnerID: order.PartnerID, Type: "receivable",
+			Amount: totalDiff, Balance: bal, Status: "open",
+			RefType: "stock_out_sale_adjust", RefID: &oid, OperatorID: userID, RecordDate: now,
+		}).Error
+	})
+}
+
 // ApproveStockOut 审核出库单，FIFO 扣减批次库存
 func (s *StockService) ApproveStockOut(shopID, orderID, reviewerID uint64) error {
 	return s.db.Transaction(func(tx *gorm.DB) error {