/weather now fetches both grids and paints each as its own canvas
overlay at its native cell size (HRRR 0.125°, HRDPS 0.5°). Server-side
chunk filtering means a US-only viewport gets an empty HRDPS pack and
vice versa — no wasted payload. /weather-ca's HRDPS-only mode is
unchanged.
Hook state moves from single (pack/overlay/abort) to per-source maps
keyed by "hrrr"|"hrdps". Render order is fixed (hrdps first, hrrr
second) so HRRR's higher-res canvas stacks on top along the border
where both sources cover the viewport.
Graham McIntire
b6fb7d2a13