Scrapes Forex Factory weekly pages (epoch datelines, actual/forecast/
impact/betterWorse) into backtest/cache/calendar.parquet (gitignored;
rebuild with the scraper). Timestamps verified: NFP/CPI/ECB times exact
across DST, and high-impact event bars average 3.5x ATR with the spike
vanishing at +/-1h shifts. calendar_store provides precise_events and
event_window_mask for screens and counterfactuals.
Harwinder Sekhon