pando login, step 2 (polled): the user and a new machine credential
Poll every interval seconds. Until the person confirms, the answer is
400 with error.code authorization_pending (keep polling) or
slow_down (add 5 seconds to the interval). access_denied,
expired_token and invalid_grant end the attempt. On success,
joined lists the monorepos (owner/name) whose email invites were accepted, and
the CLI stores credential.secret in
~/.pando/credentials/<host> (mode 600).
POST
https://app.gitpando.com/v1/login/token