Q-gap drives v_range contraction: atoms are distributed to maximize action
discrimination, not just cover the Q-range. Target: Q-gap spans 10 atoms
(20% of 52), giving C51 enough resolution for distributional value.
Decaying reward-scale floor: starts at 0.01 (breaks fixed point at init),
decays as exp(-|Q_mean|/0.01) as Q-values mature. Automatically transitions
from "Bellman projection headroom" to "tight atom resolution" without
requiring step counters or epoch awareness.
903/903 tests passing. Q-gap grows 72× (2.7e-6 → 1.93e-4) through epoch 17.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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