Slaves report pack voltages every 30s; the master caches them for fast
BATTERY_STATUS reads. goTool exposes REST/WebSocket and shows values in
the dashboard, with a nanopb fix so optional lipo submessages encode.
Co-authored-by: Cursor <cursoragent@cursor.com>
TODO: Hardware pinning in powerpod.h (TASTER_GPIO, V_LIPO_1/2_GPIO) does not
match final hardware yet — verify against schematic before production.
Co-authored-by: Cursor <cursoragent@cursor.com>