HouseFly 2.16.0 — what it learns reaches what it does

The valence memory reaches behaviour (#4). Measured on transplanted synapses alone: a smell paired with sugar gains +0.10 valence, one paired with punishment loses 0.15, an unpaired smell much less, half-life about 50 minutes, and nothing outlives its cause. Before: 0.0003, plus a reward flip-flop that held valence for hours. Fixes: dopamine neurons are modulatory (a build bug made them fast excitatory); MBONs and APL use one joint input budget; valence reads only the 47 MBONs whose Kenyon input is in the hemibrain, with the Aso 2014b sign; sugar lasts the whole meal, or 30 s of Feed. The compass now settles with a brief turn (its ignition from total stillness hung on one cell at threshold). 167 checks.