Fill quality is MALKHUT's core aim. Wired end-to-end:
1. FillQuality state (state.py):
- slippage_bps, price_improvement_bps, levels_consumed
- is_maker_fill, rolling_fill_rate, post_fill_adverse_bps
- fill_value_score: composite metric for optimization
- Added to MarketWorldState.fill_quality field
2. HftBacktestCWM.transition() (hft_cwm.py):
- _compute_fill_quality() computes all metrics per transition
- Fill quality now tracked for every CWM step
- Empty book guards added for safety
3. MinimalCryptoLOBCWM.transition() (core.py):
- Same fill quality computation for deterministic fallback
- Empty book guards added
4. Reward function (hft_cwm.py):
- fill_quality_reward = w_fill_probability * fill_value_score (PRIMARY)
- Bonus for maker fills that improve price
- Penalty for adverse selection after fill
- Base reward (PnL, adverse selection, fees) preserved
5. PerformanceMatrix (selector.py):
- RegimeStrategyScore: 4 new fill quality fields
- record(): accepts fill_rate, slippage, price_improvement, fill_value_score
- EMA updates for all fill quality metrics
6. EpisodeResult (cma_trainer.py):
- avg_fill_value_score, avg_price_improvement_bps, avg_post_fill_adverse_bps
- Accumulated per-step during _run_episode
- Recorded to PerformanceMatrix in evaluate_candidate
All 1379+ tests green.
