feat: introduce identity-backed goat

docs/BUILD_IN_PUBLIC_PLAN.md

@@ -798,15 +798,22 @@ Completed:
     stone instances stay presentation-only. Both finite trees remain reachable,
     deplete into shared stumps, restore from authoritative amount, and keep the
     world/save total at eighteen resources.
+40. `Jajce Goat 07`: Dunja is the first identity-backed animal, with a stable
+    goat ID, simulation-owned position and hunger, and a loaded cozy
+    presentation with an honest hungry cue. NPC and player feeding share one
+    exact transaction that withdraws pantry food, changes only Dunja's state,
+    and emits one economic fact. World-schema v10 save/restore preserves the
+    result without replaying the transient feed response.
 
 Next:
 
-1. Add one named goat as an identity-backed simulation vertical slice: stable
-   animal ID, authoritative position and hunger/feed state, loaded visual
-   binding, and an exact feed interaction shared by one NPC and the player.
-   Feeding must withdraw real pantry food and survive deterministic save/load.
-2. Add a small herd, breeding, or animal products only after that single-animal
-   identity and conservation contract is proven.
+1. Give Dunja one deterministic pasture/shelter routine using
+   simulation-owned destination and position, real loaded-world navigation,
+   and exact mid-move save/restore continuation.
+2. Add a second goat only after movement proves that identity remains stable
+   across care, navigation, unloading, and restore.
+3. Keep breeding, products, herd scheduling, animal spatial indexing, and
+   active/abstract simulation LOD deferred until two real animals require them.
 
 Do not start with GIS data, a full city, a large asset pack, or more NPC
 mechanics. The next proof is a beautiful stage for the systems that already