클라이언트 시크릿 DB 모델 정의 및 초기 인프라 설정

backend/internal/domain/client_secret.go

@@ -0,0 +1,21 @@
+package domain
+
+import (
+	"context"
+	"time"
+)
+
+// ClientSecret represents the stored client secret for OIDC clients.
+// Since Hydra only returns the secret once during creation, we store it here.
+type ClientSecret struct {
+	ClientID     string    `gorm:"primaryKey;column:client_id"`
+	ClientSecret string    `gorm:"column:client_secret;not null"`
+	CreatedAt    time.Time `gorm:"column:created_at"`
+	UpdatedAt    time.Time `gorm:"column:updated_at"`
+}
+
+type ClientSecretRepository interface {
+	Upsert(ctx context.Context, clientID, secret string) error
+	GetByID(ctx context.Context, clientID string) (string, error)
+	Delete(ctx context.Context, clientID string) error
+}