Apply persisted Age weather traits

docs/PORTING.md

@@ -281,6 +281,14 @@ Their grounded arrival search now begins with the floor below player Y=64 and
 works downward. If it finds no suitable footing, the existing floor-Y=63
 platform fallback places the player at Y=64.
 
+Version 0.2.19.0 applies persisted weather traits to loaded Ages. Normal uses
+Minecraft's normal weather cycle. Fast and Slow use Legacy's original duration
+and cooldown ranges at half and double normal speed for Minecraft's combined
+rain/thunder weather timer. Off keeps an Age clear;
+Always, Cloudy, Rain, and Snow maintain non-thundering precipitation; Storm
+maintains rain and thunder. Minecraft still chooses rain versus snow from biome
+temperature, so dedicated Snow/Rain biome overrides remain future work.
+
 Version 0.2.14.0 restores the legacy Linking and Descriptive Book artwork for
 inventory items and gives each book its matching open-book texture when placed
 on a Book Stand. Return Linking Books created inside another Age also retain and