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/token_service_redis.go

@@ -4,12 +4,12 @@ import (
 	"carrotskin/internal/model"
 	"carrotskin/internal/repository"
 	"carrotskin/pkg/auth"
+	"carrotskin/pkg/utils"
 	"context"
 	"errors"
 	"fmt"
 	"time"
 
-	"github.com/google/uuid"
 	"github.com/jackc/pgx/v5"
 	"go.uber.org/zap"
 )
@@ -63,9 +63,13 @@ func (s *tokenServiceRedis) Create(ctx context.Context, userID int64, UUID strin
 		}
 	}
 
-	// 生成ClientToken
+	// 生成ClientToken（使用32字符十六进制字符串）
 	if clientToken == "" {
-		clientToken = uuid.New().String()
+		var err error
+		clientToken, err = utils.RandomHex(16) // 16字节 = 32字符十六进制
+		if err != nil {
+			return selectedProfileID, availableProfiles, "", "", fmt.Errorf("生成ClientToken失败: %w", err)
+		}
 	}
 
 	// 获取或创建Client
@@ -73,7 +77,10 @@ func (s *tokenServiceRedis) Create(ctx context.Context, userID int64, UUID strin
 	existingClient, err := s.clientRepo.FindByClientToken(ctx, clientToken)
 	if err != nil {
 		// Client不存在，创建新的
-		clientUUID := uuid.New().String()
+		clientUUID, err := utils.RandomHex(16) // 16字节 = 32字符十六进制
+		if err != nil {
+			return selectedProfileID, availableProfiles, "", "", fmt.Errorf("生成ClientUUID失败: %w", err)
+		}
 		client = &model.Client{
 			UUID:        clientUUID,
 			ClientToken: clientToken,
@@ -173,6 +180,11 @@ func (s *tokenServiceRedis) Create(ctx context.Context, userID int64, UUID strin
 	return selectedProfileID, availableProfiles, accessToken, clientToken, nil
 }
 
+// CreateWithProfile 创建Token并绑定指定Profile（使用JWT + Redis存储）
+func (s *tokenServiceRedis) CreateWithProfile(ctx context.Context, userID int64, profileUUID string, clientToken string) (*model.Profile, []*model.Profile, string, string, error) {
+	return s.Create(ctx, userID, profileUUID, clientToken)
+}
+
 // Validate 验证Token（使用JWT验证 + Redis存储验证）
 func (s *tokenServiceRedis) Validate(ctx context.Context, accessToken, clientToken string) bool {
 	// 设置超时上下文