Implement plasma sword instakill

Zennysoft.Game.Ma/src/items/weapons/Weapon.cs

@@ -55,12 +55,17 @@ public partial class Weapon : EquipableItem
 
   public override int BonusDefense { get => Stats.BonusDefense + _bonusDefense; }
 
+  public override int BonusLuck { get => Stats.BonusLuck + _bonusLuck; }
+
   [Save("weapon_bonus_damage")]
   private int _bonusDamage { get; set; } = 0;
 
   [Save("weapon_bonus_damage")]
   private int _bonusDefense { get; set; } = 0;
 
+  [Save("weapon_bonus_luck")]
+  private int _bonusLuck { get; set; } = 0;
+
   [Export]
   [Save("weapon_stats")]
   public WeaponStats Stats { get; set; } = new WeaponStats();