ai.newnal.illi.account.parent.startOAuth

Start a parent's OAuth sign-in on the device through the PDN's own page (BFF), for an existing Newnal ID whose credentials are typed on the PDN page. Device-created accounts, and existing ones whose credentials the device app takes itself, sign in with account.parent.signIn instead. client=native ends with a one-time code on the device app's App Link for account.exchangeCode instead of a cookie.