Replace heavyweight JVM Clojure with Babashka for instant startup and
simplicity. The script now uses mosquitto_pub CLI tool instead of the
Java MQTT client library.
Key improvements:
- Use systemd-logind for idle detection (works with X11 and Wayland)
- Fallback to xprintidle for legacy X11-only systems
- Replace Paho MQTT client with mosquitto_pub CLI
- Eliminate all external dependencies (use Babashka built-ins)
- Add shebang for direct execution
- Fix compatibility with NixOS 25.11 and modern Wayland systems
This resolves the 'screen saver extension not supported' error by using
loginctl to query systemd-logind instead of relying on X11 extensions.
niten