HTTP management of the ESP-NOW relay peer registry — replaces the
desktop NvsConfigurator round-trip. POST {alias, mac} persists to the
NVS "peers" namespace (the exact format main.c seeds at boot) and
registers the peer live in the scenario_mesh table (no reboot). GET
lists the registry. Provisioning PLIP becomes:
curl -X POST master/game/peers -d '{"alias":"plip","mac":"..."}'
Build green (zacus_master.bin).