feat: enforce activity site capacity

simulation/actions/ActionTargetResolver.gd

@@ -14,7 +14,7 @@ func resolve(
 				npc, origin, definition, simulation_manager, active_world_adapter
 			)
 		SimulationIds.TARGET_ACTIVITY:
-			return active_world_adapter.get_activity_target(npc.current_task, origin)
+			return _resolve_activity(npc, origin, simulation_manager, active_world_adapter)
 		SimulationIds.TARGET_FREE:
 			return {
 				"target_id": "", "position": origin + simulation_manager.get_wander_offset(npc.id)
@@ -49,6 +49,36 @@ func _resolve_resource(
 	return best
 
 
+func _resolve_activity(
+	npc: SimNPC, origin: Vector3, simulation_manager: Node, active_world_adapter: Node
+) -> Dictionary:
+	if not active_world_adapter.has_method("get_activity_candidates"):
+		return active_world_adapter.get_activity_target(npc.current_task, origin)
+
+	var best: Dictionary = {}
+	var best_distance := INF
+	var candidates: Array[Dictionary] = active_world_adapter.get_activity_candidates(npc.current_task)
+	for candidate in candidates:
+		var target_id := StringName(candidate["target_id"])
+		var capacity := maxi(int(candidate.get("capacity", 1)), 1)
+		if (
+			simulation_manager.has_method("get_activity_target_claim_count")
+			and simulation_manager.get_activity_target_claim_count(target_id, npc.id) >= capacity
+		):
+			continue
+		var position: Vector3 = candidate["position"]
+		var distance := origin.distance_squared_to(position)
+		if distance < best_distance:
+			best_distance = distance
+			best = candidate
+
+	if not best.is_empty():
+		return best
+	if not candidates.is_empty():
+		return {}
+	return active_world_adapter.get_activity_target(npc.current_task, origin)
+
+
 func score_resource_candidate(
 	npc: SimNPC, origin: Vector3, position: Vector3, state: ResourceStateRecord
 ) -> float: