Mystery item implementation

Zennysoft.Game.Ma/src/items/Inventory.cs

@@ -34,6 +34,15 @@ public partial class Inventory : Node, IInventory
     return true;
   }
 
+  public bool TryInsert(InventoryItem inventoryItem, int index)
+  {
+    if (Items.Count >= _maxInventorySize || index >= _maxInventorySize || index < 0)
+      return false;
+
+    Items.Insert(index, inventoryItem);
+    return true;
+  }
+
   public void Remove(InventoryItem inventoryItem) => Items.Remove(inventoryItem);