Add campfire persistence state

Docs/TechnicalDesignDocument.md

@@ -302,6 +302,12 @@ placeholder. It is attached above the fire, starts inactive, and follows the
 same replicated lit-state visual update path as fire light intensity so final
 smoke or ember assets can be assigned later without changing gameplay code.
 
+Campfire persistence uses the shared `UAgrarianPersistentActorComponent` world
+actor path. `AAgrarianCampfire` implements the persistence-state provider hook
+to write lit state, remaining fuel, cooking enabled state, required cook time,
+and cooking progress into numeric save state, then restores those values before
+reapplying the fire visual state on load.
+
 The first real-weather adapter is `UAgrarianWeatherProviderSubsystem`. It uses
 Open-Meteo forecast requests keyed by tile center latitude/longitude, parses the
 current temperature, daily low/high, precipitation, wind, humidity, cloud cover,