The v2 PlatformIO firmware is the one in production — complete
the 48V voltage-class support started in config.h:
- config.h: imbalance tolerance 2 V in 48V class (x13/7 of the
1 V @7s fleet policy).
- BatteryParallelator.h / INAHandler.h: member defaults now come
from the config.h class macros instead of hardcoded 24000/30000
(they are overwritten by setters at setup(), defensive only).
- platformio.ini: new kxkm-s3-16MB-48v and kxkm-v3-16MB-48v envs
extending the production envs with -DBATTERY_PACK_CLASS_48V.
Validated: pio run green for kxkm-s3-16MB-48v and kxkm-s3-16MB
(default 24V unchanged), sim-host tests 13/13 pass.