- Replace broken deep-seek.ai endpoint with aichat.org relay
- Add AichatSession manager with cookie/CSRF bootstrap and auto-refresh
- Add exponential backoff retry (3 attempts) for session bootstrap
- Add all 9 aichat.org model routes via shared config (zero duplication)
- Session cookies auto-refreshed from Set-Cookie on every API response
- Auto-heal: 401 triggers session re-bootstrap + retry transparently
Co-Authored-By: Claude <noreply@anthropic.com>