Build-verify on the deploy host (2026-05-31) showed the camoufox Firefox build
landed in /root/.cache/camoufox (RUN python -m camoufox fetch ran as root), but
the runtime app user (uid 1000) resolves the cache to /home/app/.cache/camoufox
→ 'browser not found' the moment scraper_fetch_mode flips to browser.
Fix: run the fetch AFTER USER app + set explicit ENV HOME=/home/app (Docker does
not auto-set HOME from USER, and camoufox/platformdirs keys the cache off $HOME).
Now build-time fetch and runtime both use /home/app/.cache/camoufox.
Verified: A) 'camoufox path' as app = /home/app/.cache/camoufox; B) that dir was
empty pre-fix while /root/.cache was root-only (Permission denied to app).
Dormant change — scraper_fetch_mode default stays curl_cffi (no runtime behavior
change), unblocks Phase 1 (#883).
Refs #884, #883
