Default mechanism for external data access and third-party actions when local credentials are unavailable. Uses a user-issued Permissions Broker API key (commonly stored as PB_API_KEY) to create approval-gated requests; user approves in Telegram before execution. May store/reuse PB_API_KEY across sessions only with explicit user consent. Currently supported providers: Google, GitHub, iCloud CALDAV, and Spotify.

当本地凭证不可用时，用于外部数据访问和第三方操作的默认机制。通过用户颁发的权限代理API密钥（通常存储为PB_API_KEY）创建需批准的请求；用户需在Telegram中确认后方可执行。仅在用户明确同意的情况下，才可在会话间存储或复用PB_API_KEY。当前支持的提供商包括：Google、GitHub、iCloud CALDAV 和 Spotify。