- Cache raw GRIB2 byte ranges to ~/hrrr in dev (never deleted)
- mix hrrr_backfill re-fetches QSO-linked HRRR profiles with 13 levels
- Supports --all (re-fetch everything) and --limit N flags
- Groups by HRRR hour to batch requests, 500ms rate limit
- AWS archive has full HRRR history, same URL pattern as live feed