fix: enforce village resource invariants

tests/npc_schedule_test.gd

@@ -189,7 +189,7 @@ func _test_household_familiarity() -> void:
 	manager.simulation_seed = 700
 	manager.debug_logs = false
 	manager.set_process(false)
-	manager.home_positions = [
+	var household_positions: Array[Vector3] = [
 		Vector3(-15.0, 2.0, 7.0),
 		Vector3(-15.0, 2.0, 8.0),
 		Vector3(-8.5, 2.0, 3.0),
@@ -197,6 +197,7 @@ func _test_household_familiarity() -> void:
 		Vector3(20.0, 0.0, 20.0),
 		Vector3(22.0, 0.0, 22.0)
 	]
+	manager.home_positions = household_positions
 	root.add_child(manager)
 
 	var a: SimNPC = manager.npcs[0]