1. capture_training_graphs had cuStreamSynchronize before begin_capture
which hung when stream had stale state from experience collection.
2. Training profile apply_to must apply batch_size so smoketest TOML
(batch_size=64) overrides the conservative default (1024).
3. Removed batch_size from dqn-production.toml — GPU profile is authority.
4. Removed all debug eprints.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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