The tiny [64,64] smoketest network NaN's at step 22 on the full 4M bar
dataset (numerical instability — 0 compute-sanitizer errors). Production
[256,256] on H100 handles full dataset. Cap smoketest at 1000 bars
(12 steps/epoch × 10 epochs = 120 total steps, well within stability).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>