Verifies the canonical state layout at all 5 sections (market/OFI/MTF/portfolio/padding).
If any section drifts to the wrong offset, this test fails. Since training and
backtest share assemble_state() in state_layout.cuh, a passing test guarantees
both paths produce identical layouts.
Result: ✓ market=41 ofi=9 mtf=9 portfolio=5 padding=all-zero
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>