GettyLink returned HTTP 200 with a login page but the old code just re-fetched the connectivity check URL. New flow: 1. Detect portal (connectivity check != 204) 2. Follow redirects, save portal page HTML 3. Extract form action URL from the page 4. POST to the form action (accepts terms on most portals) 5. Re-check connectivity after 1s propagation delay Logs from USB showed: portal detected → auto-accept did nothing → WebSocket connections got 302 Captive Portal endlessly. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>