More abilities, refactor stealing held items

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

@@ -0,0 +1,23 @@
+namespace PkmnLib.Plugin.Gen7.Scripts.Abilities;
+
+/// <summary>
+/// Stamina is an ability that raises the user's Defense by one stage when hit by an attack.
+///
+/// <see href="https://bulbapedia.bulbagarden.net/wiki/Stamina_(Ability)">Bulbapedia - Stamina</see>
+/// </summary>
+[Script(ScriptCategory.Ability, "stamina")]
+public class Stamina : Script
+{
+    /// <inheritdoc />
+    public override void OnIncomingHit(IExecutingMove move, IPokemon target, byte hit)
+    {
+        EventBatchId batchId = new();
+        if (target.ChangeStatBoost(Statistic.Defense, 1, true, false, batchId))
+        {
+            move.Battle.EventHook.Invoke(new AbilityTriggerEvent(target)
+            {
+                BatchId = batchId,
+            });
+        }
+    }
+}