On `docker restart`, `/tmp` is preserved across container instances, so the
previous Xvfb's `/tmp/.X99-lock` survives into the new container. The new
Xvfb sees the existing lock and refuses to start, leaving the container
with no X server. Every Chrome launch then dies with "Missing X server or
$DISPLAY", and `cloakserve` returns 502 from `/json/version` forever.
Any orchestrator that restarts on unhealthy (the README-recommended
healthcheck + `restart: always`, autoheal sidecars, etc.) then enters a
permanent restart loop because every restart hits the same broken state.
This is silent for first-time users: the container appears to start
successfully (Xvfb did launch *once*), then degrades only after the first
restart. The fix is one line in the entrypoint: remove the stale lock
before starting Xvfb.
Fixes#283
Add cloakhq/cloakbrowser Docker Hub image with Node.js, JS wrapper,
Xvfb headed mode, and cloaktest shortcut. Add launch feedback and IP
display to all examples. Update README Docker section for Docker Hub.
