A session that still owes forced onboarding gets 403 setup_required from every
protected route, but the panel rendered it as the generic forbidden line — the
one step that unlocks the app read as missing authorization. api.ts now
announces the code on a window event (client module has no router) and the App
shell, inside the Router, navigates to /setup; the wizard resumes from the
surviving session with or without a token. Other 403s are untouched.
Panel tests: +2 (fires on setup_required, silent on any other 403).