v8.10.0 — Pluggable Slippage Models, Index Enhancements & Evaluation Focus

What's New

Pluggable Slippage Models (#442)

• VolumeShareSlippage — quadratic market-impact model with volume-based partial fills
• FixedBasisPointsSlippage — fixed basis-point spread model
• max_fill_amount() on SlippageModel base class for volume-aware partial fills
• TradingCost now accepts an optional slippage_model parameter
• Backtest trade-order evaluator uses TradingCost.get_max_fill_amount() for realistic fill simulation
• Full backward compatibility — existing callers are unaffected

Index & Ranking Enhancements

• rank_index(focus=...) — weighted multi-metric scoring with BacktestEvaluationFocus presets (BALANCED, PROFIT, FREQUENCY, RISK_ADJUSTED) or fully custom weights dict
• prune_backtests(flatten=True) — place pruned bundles directly in archive dir without nested folders

Documentation & Examples

• README: BacktestEvaluationFocus weighted ranking showcase with code examples and preset comparison table
• Updated trading-cost.md, blotter.md, overview.md with slippage model docs
• Tutorial notebook 03_param_sweep: uses BacktestEvaluationFocus.BALANCED for pruning workflow

Tests

• 37 new tests covering all slippage models + TradingCost integration
• All 130 existing analysis/CLI tests pass