Maps · World: choropleths and the world's countries

ChoroplethLayer washes each area by its value, keyed by its id or a
property's text or number, on one hue's scale from its faintest at the
least value to its strongest at the most; an area without a value reads
as no data. ChoroplethMap lays it on the owner's map, with or without
tiles, and puts a legend of the scale and of no data in the corner; a
value that matches no area is logged once. WorldMap washes Natural
Earth's 110m countries, bundled trimmed by scripts/countries.py, by ISO
3166 alpha-2 code, and fails on a key that is no code. A shape now
paints as one fill and one edge path per world in view.

tasks/ch31-43.md

@@ -140,7 +140,7 @@
 - [x] ProcessTable → `terminal::ProcessList`
 - [x] NetworkGraph (throughput) → `charts::RealtimeChart`
 - [x] MapView / GeoHeatmap → `maps::MapView`, `maps::GeoHeatmap` (T41a, T41b)
-- [ ] WorldMap → `maps::WorldMap` (T41c)
+- [x] WorldMap → `maps::WorldMap` (T41c)
 - [x] RefreshIntervalSelector
 - [x] DashboardFilterBar
 
@@ -305,8 +305,8 @@
 
 ## T41c Maps · World
 
-- [ ] ChoroplethMap
-- [ ] WorldMap (from T34)
+- [x] ChoroplethMap → `maps::ChoroplethMap` on a `ChoroplethLayer`: areas washed by value on one hue's scale, keyed by id or a property, with a legend; an area without a value reads as no data, a value without an area is logged once
+- [x] WorldMap (from T34) → `maps::WorldMap`, Natural Earth's 110m countries bundled and washed by ISO 3166 alpha-2 code; a key that is no code fails
 
 ## T42 Misc — `src/misc`