P0: TF32 matmuls (2-3× SGEMM throughput, 1 line each in dqn.rs + mamba2_block.rs)
P1: Checkpoint/resume every 5k steps (~50MB flat binary to PVC)
P2: Controller kernel fusion (10 launches → 1)
P3: Walk-forward 3×25k on H100 (~84 min total)
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
