Complete Meta business login

Facebook Login for Business redirect target. Meta supplies the single-use authorization code and the authenticated state returned by connectAds. The state expires after 30 minutes and binds the user, profile, Page selection and ad-account scope. No bearer token is sent by the browser. Success reconnects only metaads and redirects to the original redirect_url. Invalid state returns 400; inaccessible profiles or missing ads access cannot connect. Dashboard logins with several Pages redirect to the Facebook Page picker with an encrypted selectionToken valid for ten minutes. Listing and selecting require the initiating user and current profile access. No plaintext platform token is returned to the browser.