feat: 新增 GitHub OAuth 服务，实现用户通过 GitHub 授权登录功能。

internal/service/github_oauth_service.go

@@ -55,7 +55,10 @@ func NewGitHubOAuthService(userRepo *repository.UserRepository, authService *Aut
 		authService: authService,
 		cfg:         cfg,
 		httpClient: &http.Client{
-			Timeout: 30 * time.Second, // 澧炲姞瓒呮椂鏃堕棿
+			Timeout: 60 * time.Second,
+			Transport: &http.Transport{
+				Proxy: http.ProxyFromEnvironment,
+			},
 		},
 	}
 }