功能：平台管理员删除商户账号

backend/internal/handler/user.go

@@ -95,3 +95,12 @@ func (h *UserHandler) DeletePlatformAdmin(c *gin.Context) {
 	}
 	response.OK(c, nil)
 }
+
+func (h *UserHandler) DeleteMerchantAccount(c *gin.Context) {
+	id, _ := strconv.ParseUint(c.Param("id"), 10, 64)
+	if err := h.svc.DeleteMerchantAccount(uint(id), middleware.GetUserID(c)); err != nil {
+		response.BadRequest(c, err.Error())
+		return
+	}
+	response.OK(c, nil)
+}

backend/internal/router/router.go

@@ -195,6 +195,7 @@ func Setup(h *Handlers) *gin.Engine {
 			{
 				admin.GET("/platform/admins", h.User.ListPlatformAdmins)
 				admin.GET("/platform/merchant-accounts", h.User.ListMerchantAccountGroups)
+				admin.DELETE("/platform/merchant-accounts/:id", h.User.DeleteMerchantAccount)
 				admin.POST("/platform/admins", h.User.CreatePlatformAdmin)
 				admin.PATCH("/platform/admins/:id", h.User.UpdatePlatformAdmin)
 				admin.DELETE("/platform/admins/:id", h.User.DeletePlatformAdmin)

backend/internal/service/merchant_test.go

@@ -336,3 +336,40 @@ func TestListMerchantAccountGroupsExcludesPlatformAdmins(t *testing.T) {
 		t.Fatalf("unexpected merchant account group: %+v", groups[0])
 	}
 }
+
+func TestDeleteMerchantAccountRemovesAllMemberships(t *testing.T) {
+	db := newServiceTestDB(t)
+	merchantA := model.Merchant{Code: "delete-account-a", Name: "删除账号商户 A", Status: model.MerchantStatusActive}
+	merchantB := model.Merchant{Code: "delete-account-b", Name: "删除账号商户 B", Status: model.MerchantStatusActive}
+	merchantUser := model.User{Username: "delete-merchant-account", PasswordHash: "hash", Role: model.RoleMerchant, Status: 1}
+	platformAdmin := model.User{Username: "delete-account-admin", PasswordHash: "hash", Role: model.RoleAdmin, Status: 1}
+	for _, entity := range []interface{}{&merchantA, &merchantB, &merchantUser, &platformAdmin} {
+		if err := db.Create(entity).Error; err != nil {
+			t.Fatalf("create fixture: %v", err)
+		}
+	}
+	for _, member := range []model.MerchantMember{
+		{MerchantID: merchantA.ID, UserID: merchantUser.ID, Role: model.MemberRoleOperator, Status: 1},
+		{MerchantID: merchantB.ID, UserID: merchantUser.ID, Role: "support", Status: 1},
+	} {
+		if err := db.Create(&member).Error; err != nil {
+			t.Fatalf("create membership: %v", err)
+		}
+	}
+
+	svc := NewUserService(db, nil)
+	if err := svc.DeleteMerchantAccount(merchantUser.ID, platformAdmin.ID); err != nil {
+		t.Fatalf("delete merchant account: %v", err)
+	}
+	var memberships int64
+	if err := db.Model(&model.MerchantMember{}).Where("user_id = ?", merchantUser.ID).Count(&memberships).Error; err != nil || memberships != 0 {
+		t.Fatalf("merchant memberships should be removed, count=%d err=%v", memberships, err)
+	}
+	var deleted model.User
+	if err := db.Unscoped().First(&deleted, merchantUser.ID).Error; err != nil || !deleted.DeletedAt.Valid {
+		t.Fatalf("merchant account should be soft deleted, user=%+v err=%v", deleted, err)
+	}
+	if err := svc.DeleteMerchantAccount(platformAdmin.ID, merchantUser.ID); err == nil {
+		t.Fatal("platform administrator should not be deletable from merchant account endpoint")
+	}
+}

backend/internal/service/user.go

@@ -316,3 +316,31 @@ func (s *UserService) DeletePlatformAdmin(id, actorUserID uint) error {
 		return tx.Delete(&user).Error
 	})
 }
+
+// DeleteMerchantAccount permanently removes a merchant login account and all
+// of its merchant memberships. Platform administrators must be managed from
+// the dedicated platform administrator view instead.
+func (s *UserService) DeleteMerchantAccount(id, actorUserID uint) error {
+	if id == 0 {
+		return errors.New("用户不存在")
+	}
+	if id == actorUserID {
+		return errors.New("不能删除当前登录账号")
+	}
+	return s.db.Transaction(func(tx *gorm.DB) error {
+		var user model.User
+		if err := tx.First(&user, id).Error; err != nil {
+			if errors.Is(err, gorm.ErrRecordNotFound) {
+				return errors.New("用户不存在")
+			}
+			return err
+		}
+		if user.Role != model.RoleMerchant {
+			return errors.New("平台管理员请在平台管理员列表中管理")
+		}
+		if err := tx.Where("user_id = ?", user.ID).Delete(&model.MerchantMember{}).Error; err != nil {
+			return err
+		}
+		return tx.Delete(&user).Error
+	})
+}