Subscribes to posbriefing/button/press; on PRESS runs pos_briefing.py as a
subprocess (debounced via a lock) and reports status/availability. Registers an
HA button via MQTT discovery. Pins paho CallbackAPIVersion.VERSION1 (paho 2.1.0
is installed for claude and warns on the implicit default).
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Mortdecai