fix(backend): JWT config mapstructure tag 修复 + 模型从 hotel 重构为 shop

- 修复 JWTConfig 缺少 mapstructure tag 导致 access_expire_min 解析为 0，
  token 签发即过期，所有 API 请求返回 401
- 全部 config struct 补齐 mapstructure tag（secret/dsn/hmac_secret 等）
- 模型层从 hotel/HotelID 统一重命名为 shop/ShopID
- 删除旧 migrations（001-004），新增 001_init 综合迁移文件
- 更新 schema.sql、testutil、handler/service/model 相关引用

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

backend/internal/handler/partner.go

@@ -20,12 +20,12 @@ func NewPartnerHandler(db *gorm.DB) *PartnerHandler {
 }
 
 func (h *PartnerHandler) List(c *gin.Context) {
-	hotelID := middleware.GetHotelID(c)
+	shopID := middleware.GetShopID(c)
 	page, _ := strconv.Atoi(c.DefaultQuery("page", "1"))
 	pageSize, _ := strconv.Atoi(c.DefaultQuery("page_size", "20"))
 
 	query := h.db.Model(&model.Partner{}).
-		Where("hotel_id = ? AND deleted_at IS NULL", hotelID)
+		Where("shop_id = ? AND deleted_at IS NULL", shopID)
 
 	if t := c.Query("type"); t != "" {
 		query = query.Where("FIND_IN_SET(?, type)", t)
@@ -44,13 +44,13 @@ func (h *PartnerHandler) List(c *gin.Context) {
 }
 
 func (h *PartnerHandler) Create(c *gin.Context) {
-	hotelID := middleware.GetHotelID(c)
+	shopID := middleware.GetShopID(c)
 	var p model.Partner
 	if err := c.ShouldBindJSON(&p); err != nil {
 		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
 		return
 	}
-	p.HotelID = hotelID
+	p.ShopID = shopID
 	if err := h.db.Create(&p).Error; err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
 		return
@@ -59,9 +59,9 @@ func (h *PartnerHandler) Create(c *gin.Context) {
 }
 
 func (h *PartnerHandler) Update(c *gin.Context) {
-	hotelID := middleware.GetHotelID(c)
+	shopID := middleware.GetShopID(c)
 	var p model.Partner
-	if err := h.db.Where("id = ? AND hotel_id = ? AND deleted_at IS NULL", c.Param("id"), hotelID).
+	if err := h.db.Where("id = ? AND shop_id = ? AND deleted_at IS NULL", c.Param("id"), shopID).
 		First(&p).Error; err != nil {
 		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})
 		return
@@ -70,16 +70,16 @@ func (h *PartnerHandler) Update(c *gin.Context) {
 		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
 		return
 	}
-	p.HotelID = hotelID
+	p.ShopID = shopID
 	h.db.Save(&p)
 	c.JSON(http.StatusOK, gin.H{"data": p})
 }
 
 func (h *PartnerHandler) Delete(c *gin.Context) {
-	hotelID := middleware.GetHotelID(c)
+	shopID := middleware.GetShopID(c)
 	now := timeNow()
 	result := h.db.Model(&model.Partner{}).
-		Where("id = ? AND hotel_id = ? AND deleted_at IS NULL", c.Param("id"), hotelID).
+		Where("id = ? AND shop_id = ? AND deleted_at IS NULL", c.Param("id"), shopID).
 		Update("deleted_at", now)
 	if result.RowsAffected == 0 {
 		c.JSON(http.StatusNotFound, gin.H{"error": "not found"})