Every rated run now pulls proportionally to its own reward instead of
being bucketed into two equal-weight groups -- a 9/10 counts for more
than a 6/10, instead of both counting as one full vote. Centring the
WEIGHTS (not the descriptors) before the weighted sum is what makes
shared content cancel exactly even when the weights are unbalanced;
see the module docstring for the identity. This is what actually
justifies the scale existing at all, rather than just picking one of
two buckets with extra steps.
Also: the H3 scale's heart/loved button did nothing --
normalize_refiner_v2_rating only applies the loved boost inside the
branch that matches an existing category label, and a bare number
never reaches it (confirmed: '7' and '7|loved' produced the identical
reward). Removed it from the scale rather than wire a boost with no
established meaning on a 1-10 input.