Move all battle state from IPokemon to an ephemeral IBattlePokemon wrapper

Plugins/PkmnLib.Plugin.Gen7/Scripts/Abilities/ShedSkin.cs

@@ -8,12 +8,12 @@ namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
 [Script(ScriptCategory.Ability, "shed_skin")]
 public class ShedSkin : Script, IScriptOnEndTurn
 {
-    private IPokemon? _owningPokemon;
+    private IBattlePokemon? _owningPokemon;
 
     /// <inheritdoc />
     public override void OnAddedToParent(IScriptSource source)
     {
-        if (source is not IPokemon pokemon)
+        if (source is not IBattlePokemon pokemon)
             throw new ArgumentException("ShedSkin script must be added to a Pokemon.", nameof(source));
         _owningPokemon = pokemon;
     }