Secure OAuth token management via Scalekit. Handles token storage, refresh, and retrieval for third-party services (Gmail, Slack, GitHub, etc.). Never stores tokens locally - always fetches fresh tokens from Scalekit.

通过 Scalekit 实现安全的 OAuth 令牌管理，负责第三方服务（如 Gmail、Slack、GitHub 等）的令牌存储、刷新和获取。绝不本地存储令牌，始终从 Scalekit 获取最新令牌