Add a board-aware battery SOC system replacing the two independent
linear approximations that existed in the UI helpers.
New helpers/battery_curve.{h,c}: a 21-point (5% step) OCV lookup table
with integer linear interpolation. The default generic LiPo curve is a
weak symbol — any board can override it by dropping a battery_curve.c
into its board directory. CMakeLists.txt selects the board-specific file
when present, falling back to the generic.
Board.h gains getBattPercent() (default 0); ZephyrBoard implements it
via battery_curve_lookup().
Board-specific curves added for boards with measured cell data:
t1000_e, rak_wismesh_tag, thinknode_m6, sensecap_solar, wio_tracker_l1.
ADC multiplier corrections applied across all nRF52840 boards:
- Boards using a correctly-derived 3600×ratio formula get +0.5% to
compensate for nRF SAADC gain error (7200→7236, 6300→6332, etc.)
- rak_wismesh_tag, rak3401_1watt, gat562_30s had multipliers copied
from Arduino's 3.0V AREF formula; corrected to 3600×1.73×1.005=6259
- xiao_nrf52840 (10911) left unchanged — empirically calibrated value
above the theoretical, assumed already correct for that hardware
get adc.multiplier now reports current mV reading and the board's
curve 100% target, making field calibration self-guiding.
- flood retransmit jitter now capped at min(2000ms, 6·airtime) instead of
fixed 2000ms — spreads tighter at SF7, unchanged at SF8
- reactive per-dupe backoff cap now min(2000ms, 12·airtime), keeps
semantic of "push past ~12 relay slots"
- contention ring 16 → 24 for 50-neighbor hilltops
- companions passively track heard floods (warms EMA without forwarding)
and spread their own TX by up to min(1000ms, 3·airtime), hopefully
fixing repeaters missing companion's first transmission
config cleanup:
- move BLE TX buffer bumps (ACL_TX=12 etc.) from zephcore_common.conf to
esp32_common.conf — the Espressif blob needs them, nRF doesn't, and
the bumps were overflowing nRF52840 RAM
- remove CONFIG_ZEPHCORE_MAX_CONTACTS=510 overrides from 5 nRF52840
companion boards; Kconfig default of 350 fits with comfortable margin
(wio prod: 91% → 79% RAM)
liquidraver