Root cause: camoufox-js@0.11.0 fetch can exit 0 but silently fail
to download the browser binary when:
1. A partial/incomplete cache from a previous run exists
2. GitHub API rate-limits the unauthenticated release query
3. Network drops mid-download
Fix:
1. run_fetch() now DELETE incomplete cache (dir exists but no
version.json) before fetching — prevents 'already cached' no-op
2. After fetch, VERIFY version.json exists — if missing, RETRY once
3. After retry, verify Camoufox.app/Contents/MacOS/camoufox exists
4. Log stdout and stderr in INFO traces for debugging
Tara Menon
9851e41182