更新依赖项，添加单元测试，优化用户信息和令牌管理功能，增强中间件以支持 JWT 验证，新增访问令牌模型并更新数据库迁移。

services/oauth.go

@@ -174,7 +174,7 @@ func (s *OAuthService) ExchangeToken(req *TokenRequest) (*TokenResponse, error)
 	}
 
 	// 生成访问令牌
-	accessToken, err := s.generateAccessToken(user, client, authCode.Scope)
+	accessToken, err := s.GenerateAccessToken(user, client, authCode.Scope)
 	if err != nil {
 		return nil, err
 	}
@@ -197,17 +197,18 @@ func (s *OAuthService) ExchangeToken(req *TokenRequest) (*TokenResponse, error)
 	}, nil
 }
 
-func (s *OAuthService) generateAccessToken(user *models.User, client *models.Client, scope string) (string, error) {
+func (s *OAuthService) GenerateAccessToken(user *models.User, client *models.Client, scope string) (string, error) {
 	now := time.Now()
 	claims := jwt.MapClaims{
-		"sub":   user.ID,
+		"sub":   fmt.Sprintf("%d", user.ID),
+		"iss":   client.ClientID,
+		"aud":   client.ClientID,
 		"exp":   now.Add(s.tokenTTL).Unix(),
 		"iat":   now.Unix(),
-		"iss":   client.ClientID,
 		"scope": scope,
 	}
 
-	token := jwt.NewWithClaims(jwt.SigningMethodHS256, claims)
+	token := jwt.NewWithClaims(jwt.SigningMethodRS256, claims)
 	return token.SignedString(s.keyManager.GetPrivateKey())
 }