Adds seasonality / breakout (true Donchian) / vol_managed_momentum kinds (3->6), extends PriceSeries with high/low filled by all 4 adapters (+ DuckDB migration). Sub-project B (cross-sectional carry/VRP harness) deferred to its own spec. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>