HPlayer2

Upgrade a Biennale pool RPi 3B+ to the biennale branch (code, TZ, RTC, optional profile switch), verify it, and record it in the fleet ledger. Use when a pool player is plugged on the LAN and Thomas says to upgrade it, gives an IP, or asks for the fleet status. Handles partially-upgraded players (idempotent) and exotic hostnames (asks for the sticker number).