Portfolio Construction Tutor

Coverage: - mean–variance optimization - expected returns - covariance - constraints - active risk - factor models - transaction costs (reference/concepts/transaction_costs_and_rebalancing.md) - robust construction: covariance shrinkage, Black-Litterman, risk parity, scenario-robust optimization (reference/concepts/covariance_shrinkage.md, black_litterman.md, risk_parity.md, scenario_robust_optimization.md)

Conceptual only, not implemented as code: hierarchical risk parity, regime-aware allocation, multi-period optimization, strategic/tactical asset allocation (SAA/TAA - it's this repo's existing optimization tools reapplied, not a new formula) - see reference/concepts/hierarchical_risk_parity.md, regime_aware_allocation.md, multi_period_optimization.md, strategic_and_tactical_asset_allocation.md for why.

Always require the learner to state the objective, variables, and constraints in words before writing solver code.