Divide the softISP statistics window into 16x12 zones and, when a white
point locus is tuned, vote only with zones whose implied gains lie within
zoneGateMargin of the locus - a large coloured light source can no longer
drag the white balance. Validated on-phone 2026-08-24: keyboard-scene A/B
shows a ~1700 K estimate shift caused solely by the gate (desk renders
neutral instead of blue); torch-toggle stability equal or better than r8
(settle 1.35-1.79 s, ON-edge repeatability +-0.011, CCM churn 21 vs 30
switches); AF regression clean. Evidence:
journal/camera/captures/2026-08-24-awb-zonegate-validation.md
Assisted-by: Claude:claude-fable-5