ported from perforce

RobotAndDonkey.Game/Modifiers/PersistentModifier.cs

@@ -0,0 +1,14 @@
+using System;
+using System.Collections.Generic;
+using RobotAndDonkey.Game.Execution.Results;
+using RobotAndDonkey.Game.GameState;
+using RobotAndDonkey.Game.Intents;
+
+namespace RobotAndDonkey.Game.Modifiers;
+
+public record PersistentModifier(EModifierDuration Duration) : Modifier(EModifierKind.Card, EModifierId.Persistent, Duration)
+{
+    protected override PersistentModifier CreateInstance() => new(Duration);
+
+    public override string ToolTip => "This instruction is not discarded after execution.";
+}