Module auth 

OAuth2 authentication: PKCE loopback flow (RFC 8252) with an RFC 8628 device-flow fallback, tokens in the OS keyring.

Multi-account: one OAuth client, one token per Google account. An auth handle is bound to one account’s store entry (the default account keeps the legacy naming byte-for-byte); named accounts log in independently.

Structs

AuthConfigBuilder

DeviceAuthChallenge

Pending device authorization: show verification_url + user_code to the user, then poll with super::GoogleAuth::poll_device_code until done.

GoogleAuth

OAuth2 client with PKCE support

TokenStorage

Token storage with automatic refresh.

Constants

SCOPES

Union of every service’s scopes (Gmail, Calendar, Drive, People, Chat, Forms). Least-privilege selection is deliberately not implemented: one credential, everything works, nothing to configure.