Demand Anomalies

Flag a period where a material's demand history reflects a known supply-side anomaly (e.g. a shortage-driven backlog of open work orders) rather than real recurring demand. Months inside an active window are treated as zero demand when the engine classifies that material — not deleted from history, just excluded from ADI/CV²/seasonality math. Ships empty by design: nothing is pre-populated here, only real confirmed anomalies should be added. Takes effect on the next npm run run-engine, not retroactively on already-computed ParamVersions.