Implement climate and weather features in world simulation; enhance API with weather retrieval and climate selection options, update UI to support climate selection during world creation, and improve weather display in the game interface.

AGENTS.md

@@ -66,7 +66,13 @@ The Living World is a web game whose map is a real place: the API imports OpenSt
 
 Worlds are stored as files under `data/` (not committed). Cap: `WorldStorage:MaxConcurrentWorlds`.
 Ready worlds run a live game clock on the server (5 game minutes per real second at x1; default start
-12 April 2012 06:00). UI: main menu (list + create) → map screen with pause and speed controls.
+12 April 2012 06:00) plus weather: a Köppen-lite climate preset per world, with drifting pressure systems as
+ECS entities on top of a deterministic seasonal/diurnal baseline. UI: main menu (list + create, with a climate
+picker) → map screen with pause, speed, clock and weather, and a renderer that washes the map for time of
+day, cloud, fog and lying snow and drops rain or snow through it.
+
+New ECS components must be added to the probe entity in `SimulationComponents` — Arch assigns component type
+ids on first use without a lock, and two threads racing there hand out the same id.
 
 Keep wire DTOs in sync: `TheLivingWorld.Core.Contracts` and `src/TheLivingWorld.Web/src/api/types.ts`.