Prophet Regressor Integration — Events are incorporated as external regressors in the forecasting model. Each event contributes a regressor component that is added to trend + seasonality, and widens the confidence interval proportionally to the magnitude. This mirrors how Meta's Prophet handles add_regressor() calls.

Scoped Holiday Regressors — Each calendar can be targeted to specific SKUs or categories and specific regions. A US Black Friday calendar scoped to Electronics + Northeast will only influence Electronics SKUs forecasted in the Northeast region.