What’s being calculated
Z = Σ (weightcat · zcat) using SportsWZRD’s z-score baselines (incl. FG/FT attempt weighting, TO inverted).
WZRD = normalize(Z) to a 0–100 scale.
Surprise = w₁·(gameZ − seasonAvgZ) + w₂·max(0, gameZ), with weights normalized to sum to 1.