- src/lib/regions.ts (new): cached, turf-free same-origin fetches of
/region-keys.json (feature id -> key) and /regions.geo.json (id -> name) so
WorldMap and NationPanel share one fetch each.
- WorldMap.tsx: stamps each feature's properties.regionKey (from the manifest,
by its stable id) and resolves owner / flash / hover / click from that key via
the shared mapFeatureOwner; the per-region flash lights the exact sub-region
whose owner changed; click carries only the sub-region name.
- NationPanel.tsx: territory chips show the region's human name (falling back
to the raw key) with the key in the title / data-attr.
- App.tsx: the selected-region dossier label drops the now-unused parent code.
