feat: scale village queries and enrich Jajce center

tests/jajce_runtime_integration_test.gd

@@ -31,6 +31,11 @@ func _run() -> void:
 	await process_frame
 
 	_check(simulation_manager.npcs.size() == 6, "Baseline should create six NPCs")
+	var runtime_player := main_scene.get_node("Player") as Node3D
+	_check(
+		runtime_player.is_in_group("grass_interactors"),
+		"The real player transform should drive nearby grass response"
+	)
 	var inspector_label := (
 		main_scene.get_node("UI/NpcInspectorPanel/MarginContainer/NpcInspectorLabel") as Label
 	)
@@ -60,6 +65,26 @@ func _run() -> void:
 		"Runtime knowledge UI check should use a completed simulation transaction"
 	)
 	var world_view := main_scene.get_node("WorldViewManager")
+	var all_npc_visuals_drive_grass := true
+	for npc_visual in world_view.active_npc_visuals.values():
+		all_npc_visuals_drive_grass = (
+			all_npc_visuals_drive_grass and (npc_visual as Node3D).is_in_group("grass_interactors")
+		)
+	_check(
+		all_npc_visuals_drive_grass,
+		"Every active villager visual should drive local grass response"
+	)
+	var grass_material := (
+		main_scene.get_node("JajceWorld/TerrainRoot/Terrain3D/CozyGrassField").get(
+			"mesh_material_override"
+		)
+		as ShaderMaterial
+	)
+	var grass_interactor_count := int(grass_material.get_shader_parameter("interactor_count"))
+	_check(
+		grass_interactor_count in range(1, 9),
+		"Grass shader should receive a bounded set of real nearby actor transforms"
+	)
 	var contributor_visual: Node3D = world_view.active_npc_visuals[contributor.id]
 	var witness_visual: Node3D = world_view.active_npc_visuals[witness.id]
 	var listener_visual: Node3D = world_view.active_npc_visuals[listener.id]