Fix ActionSet

Solver/ActionSet.cs

@@ -16,7 +16,7 @@ public struct ActionSet
     private static int FromAction(ActionType action)
     {
         var ret = Simulator.AcceptedActionsLUT[(byte)action];
-        if (ret == 0)
+        if (ret == -1)
             throw new ArgumentOutOfRangeException(nameof(action), action, $"Action {action} is unsupported in {nameof(ActionSet)}.");
         return ret;
     }

Solver/Simulator.cs

@@ -63,6 +63,8 @@ public sealed class Simulator : SimulatorNoRandom
     static Simulator()
     {
         AcceptedActionsLUT = new int[Enum.GetValues<ActionType>().Length];
+        for (var i = 0; i < AcceptedActionsLUT.Length; i++)
+            AcceptedActionsLUT[i] = -1;
         for (var i = 0; i < AcceptedActions.Length; i++)
             AcceptedActionsLUT[(byte)AcceptedActions[i]] = i;
     }