feat(yggdrasil): implement standard error responses and UUID format improvements

- Add YggdrasilErrorResponse struct and standard error codes for protocol compliance
- Change UUID storage from varchar(36) to varchar(32) for unsigned format
- Add utility functions: GenerateUUID, FormatUUIDToNoDash, RandomHex
- Support unsigned query parameter in GetProfileByUUID endpoint
- Improve refresh token response with available profiles list
- Fix key pair retrieval to use correct database column (rsa_private_key)
- Update UUID validator to accept both 32-char and 36-char formats
- Add SignStringWithProfileRSA method for profile-specific signing
- Fix profile assignment validation in refresh token flow

internal/service/interfaces.go

@@ -79,6 +79,7 @@ type TextureService interface {
 type TokenService interface {
 	// 令牌管理
 	Create(ctx context.Context, userID int64, uuid, clientToken string) (*model.Profile, []*model.Profile, string, string, error)
+	CreateWithProfile(ctx context.Context, userID int64, profileUUID string, clientToken string) (*model.Profile, []*model.Profile, string, string, error)
 	Validate(ctx context.Context, accessToken, clientToken string) bool
 	Refresh(ctx context.Context, accessToken, clientToken, selectedProfileID string) (string, string, error)
 	Invalidate(ctx context.Context, accessToken string)
@@ -116,6 +117,7 @@ type YggdrasilService interface {
 
 	// 序列化
 	SerializeProfile(ctx context.Context, profile model.Profile) map[string]interface{}
+	SerializeProfileWithUnsigned(ctx context.Context, profile model.Profile, unsigned bool) map[string]interface{}
 	SerializeUser(ctx context.Context, user *model.User, uuid string) map[string]interface{}
 
 	// 证书