New "Weather radar" toggle in /map's control panel (mobile + desktop)
layers an ECCC GeoMet WMS composite dBZ mosaic over the propagation
heatmap. The Radar_1km_dBZ-Extrapolation layer covers CONUS + Canada at
1 km resolution, updated every ~6 minutes. Tiles are lazy-created on
first toggle so visitors who never open the panel never hit the WMS
service. Refresh is driven by a setInterval that calls setParams with a
cache-busting timestamp, matching ECCC's publish cadence.
Rain-scatter display (NEXRAD cell markers + "Rain Scatter" section in
the point-detail panel) is disabled for now. The live radar overlay
answers "is there rain near this point?" more directly, and the scatter
propagation feature needs more work before it's useful. The Elixir
start_async, handle_async, and fetch_rain_scatter helpers are removed.
The JS drawScatterMarkers / buildScatterBlock paths remain as harmless
dead code since they're guarded by a `rain_scatter` field the server no
longer sends — easy to re-enable later by restoring the payload key.
Graham McIntire
85036eff21