CLI auth
The device login the `syndai` CLI uses to get an API key: start a login, show the user code to a person to approve in the browser, then poll for the key. Unapproved polls answer with OAuth device-flow errors.
The device login the `syndai` CLI uses to get an API key: start a login, show the user code to a person to approve in the browser, then poll for the key. Unapproved polls answer with OAuth device-flow errors.