Full current-conditions report for a California region.

Use this for area-scale questions ("how is the Bay Area?", "what's
happening in SoCal?") instead of stitching together point queries. It
sweeps every source over the whole region at once: CHP incidents
(severity-sorted, worst first), lane closures in place (full closures
called out), chain controls, and wildfires inside the region.

Regions: Bay Area, Sacramento metro, Tahoe/Sierra, Central Valley,
Southern California, San Diego, Central Coast, North State. An
unrecognized region name returns the list.

Large regions are capped to the most severe items; the counts are
always exact and the response says when a list was truncated.
Freshness: CHP ~1/min fetched live, everything else 5-minute cache.