deviceAuthorization

Starts the device authorization flow and polls for the token.

Emits DeviceFlowStatus.Started immediately after obtaining the device code, then emits DeviceFlowStatus.Polling while waiting for authorization or retrying a transient transport failure. Transient token-endpoint failures are retried with bounded backoff while the device code remains valid. The flow continues until one of the terminal states is reached:

• DeviceFlowStatus.Success — access token received and stored.

• DeviceFlowStatus.Expired — device code expired.

• DeviceFlowStatus.AccessDenied — user denied the authorization request.

• DeviceFlowStatus.Failure — unrecoverable error occurred.

The flow closes automatically after emitting any terminal state.