Every JS/cookie-based detection approach failed. Reverting to the
simplest reliable mechanism: if the WebView navigates to any non-login,
non-auth URL, the server redirected us after sign-in — fire onAuthenticated.
Also removing the browser headers added in beta.6. The 1.1.4 version
worked without them and they may be triggering server-side bot detection.
All-cookies approach (beta.8) is kept.