binary_sensor.dsc_flow_mass_balance_ok compared two mutually-derived allocations, so it could never fail honestly

Found 2026-09-08 while diagnosing the over-pressure report. The check was abs(total_intake – total_exhaust) where total_intake is the sum of the intake allocated sensors (Sigma-exhaust-capacity split by intake fan pct) and total_exhaust is the sum of the exhaust allocated sensors (Sigma-intake-capacity split by exhaust fan pct). The two are computed from opposite bases, so the comparison never tested the rig — it compared each side against the other’s mirror. Rebased on capacity vs capacity and given the net pressure in its attributes. Note the chip is still gated on Climate (not a live alarm), so this was invisible.