Evaluation Spec

Deterministic parity with the Foredeck server:

bucket = int(md5(f"{unit_id}_{salt}").hexdigest()[:8], 16) % 100

Variations are walked in descending weight order accumulating weight; the first variation where bucket < cumulative wins. Disabled flags return the control variation with reason DISABLED. The machine-readable conformance fixtures live in spec/evaluation-spec.json — ports to other languages must pass those cases.