병합 오류 수정

backend/internal/domain/relying_party.go

@@ -10,7 +10,7 @@ import (
 // It maps 1:1 to a Hydra Client.
 type RelyingParty struct {
 	ClientID    string         `gorm:"primaryKey" json:"clientId"` // Maps to Hydra Client ID
-	TenantID    string         `gorm:"index;not null" json:"tenantId"`
+	TenantID    string         `gorm:"index" json:"tenantId"`
 	Name        string         `json:"name"` // Display name (can be same as Hydra Client Name)
 	Description string         `json:"description"`
 	CreatedAt   time.Time      `json:"createdAt"`