init: 后端框架脚手架 (Go + Gin + GORM + MySQL)

- 项目目录结构：backend/ deploy/ schema/ migrations/
- 数据库 Schema：所有建表 SQL，含 hotel_id 多租户隔离
- Go 后端：config、model、handler、service、middleware、router
- 认证：账号密码登录 + JWT（Access + Refresh Token）
- 许可证：HMAC-SHA256 激活码生成 + 设备绑定验证
- 业务模块：商品、仓库、往来单位、入库、出库、库存、盘点
- 库存事务：入库/出库审核时原子更新库存 + 流水记录
- 数据导入：Excel/CSV 批量导入商品、往来单位
- Docker Compose：本地 MySQL + Adminer

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/internal/handler/import.go

@@ -0,0 +1,157 @@
+package handler
+
+import (
+	"net/http"
+	"strings"
+
+	"github.com/gin-gonic/gin"
+	"github.com/xuri/excelize/v2"
+	"gorm.io/gorm"
+
+	"github.com/wangjia/jiu/backend/internal/middleware"
+	"github.com/wangjia/jiu/backend/internal/model"
+)
+
+type ImportHandler struct {
+	db *gorm.DB
+}
+
+func NewImportHandler(db *gorm.DB) *ImportHandler {
+	return &ImportHandler{db: db}
+}
+
+// ImportProducts POST /api/v1/import/products
+// 支持 .xlsx / .csv，列顺序：名称,系列,规格,单位,品牌,进价,售价,最低库存,备注
+func (h *ImportHandler) ImportProducts(c *gin.Context) {
+	hotelID := middleware.GetHotelID(c)
+
+	file, err := c.FormFile("file")
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "file required"})
+		return
+	}
+
+	f, err := file.Open()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	defer f.Close()
+
+	xl, err := excelize.OpenReader(f)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid excel file: " + err.Error()})
+		return
+	}
+
+	sheetName := xl.GetSheetName(0)
+	rows, err := xl.GetRows(sheetName)
+	if err != nil || len(rows) < 2 {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "empty or invalid sheet"})
+		return
+	}
+
+	var products []model.Product
+	var errRows []map[string]interface{}
+
+	for i, row := range rows[1:] { // 跳过表头
+		if len(row) < 1 || strings.TrimSpace(row[0]) == "" {
+			continue
+		}
+		p := model.Product{
+			TenantBase: model.TenantBase{HotelID: hotelID},
+		}
+		p.Name = cell(row, 0)
+		p.Series = cell(row, 1)
+		p.Spec = cell(row, 2)
+		p.Unit = cell(row, 3)
+		p.Brand = cell(row, 4)
+		p.Remark = cell(row, 8)
+
+		if p.Name == "" {
+			errRows = append(errRows, map[string]interface{}{"row": i + 2, "error": "name is empty"})
+			continue
+		}
+		products = append(products, p)
+	}
+
+	if len(products) == 0 {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "no valid rows", "errors": errRows})
+		return
+	}
+
+	// 批量写入（upsert by hotel_id+name+spec）
+	if err := h.db.CreateInBatches(&products, 100).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"imported": len(products),
+		"errors":   errRows,
+	})
+}
+
+// ImportPartners POST /api/v1/import/partners
+// 列顺序：名称,类型(supplier/customer),联系人,电话,地址,备注
+func (h *ImportHandler) ImportPartners(c *gin.Context) {
+	hotelID := middleware.GetHotelID(c)
+
+	file, err := c.FormFile("file")
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "file required"})
+		return
+	}
+
+	f, err := file.Open()
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	defer f.Close()
+
+	xl, err := excelize.OpenReader(f)
+	if err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "invalid excel file"})
+		return
+	}
+
+	rows, err := xl.GetRows(xl.GetSheetName(0))
+	if err != nil || len(rows) < 2 {
+		c.JSON(http.StatusBadRequest, gin.H{"error": "empty sheet"})
+		return
+	}
+
+	var partners []model.Partner
+	for _, row := range rows[1:] {
+		if len(row) < 1 || strings.TrimSpace(row[0]) == "" {
+			continue
+		}
+		t := cell(row, 1)
+		if t == "" {
+			t = "supplier"
+		}
+		partners = append(partners, model.Partner{
+			TenantBase: model.TenantBase{HotelID: hotelID},
+			Name:       cell(row, 0),
+			Type:       t,
+			Contact:    cell(row, 2),
+			Phone:      cell(row, 3),
+			Address:    cell(row, 4),
+			Remark:     cell(row, 5),
+		})
+	}
+
+	if err := h.db.CreateInBatches(&partners, 100).Error; err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+	c.JSON(http.StatusOK, gin.H{"imported": len(partners)})
+}
+
+func cell(row []string, idx int) string {
+	if idx >= len(row) {
+		return ""
+	}
+	return strings.TrimSpace(row[idx])
+}