Put app/services/fetcher.py

Put app/services/fetcher.py

Put app/services/fetcher.py

Put app/services/fetcher.py

3-stage fetch: httpx, then headless Chromium, then headed Chromium (Xvfb); report exact per-stage results

add headless-Chromium render fallback that auto-triggers on 403 or Cloudflare challenge

send full browser-like headers so bot-protected sites like chatgpt.com are not 403-blocked

add asset fetcher