fix: CreateUser 핸들러 내 누락된 LoginID 필드 추가 및 오타 수정

backend/internal/handler/user_handler.go

@@ -258,6 +258,7 @@ func (h *UserHandler) CreateUser(c *fiber.Ctx) error {
 
 	var req struct {
 		Email       string         `json:"email"`
+		LoginID     string         `json:"loginId"`
 		Password    string         `json:"password"`
 		Name        string         `json:"name"`
 		Phone       string         `json:"phone"`
@@ -357,7 +358,7 @@ func (h *UserHandler) CreateUser(c *fiber.Ctx) error {
 
 	brokerUser := &domain.BrokerUser{
 		Email:       email,
-		LoginID:     extractString(attributes, "id"),
+		LoginID:     extractTraitString(attributes, "id"),
 		Name:        name,
 		PhoneNumber: normalizePhoneNumber(req.Phone),
 		Attributes:  attributes,