Logout: Simulate Altenar ending the session — same pattern as login (postMessage).
Perform logout on your platform first if needed; then send TERMINAL_LOGOUT so the iframe clears
cookies and returns to home.
⚠ Register flow: MitID cannot run inside an iframe (browser blocks
third-party cookies). The app navigates this entire tab to MitID.
After completion it redirects to the returnUrl above
(defaults to this test page), so you land right back here.
Waiting for IFRAME_READY…