Implement basic structure for combat system and refactor code

Assets/Scripts/Combat/LazyStack.cs

@@ -0,0 +1,30 @@
+using System;
+using System.Collections.Generic;
+
+namespace KernelPanic.Combat
+{
+    /// <summary>
+    /// Stores played cards in LIFO order until explicitly force-evaluated.
+    /// </summary>
+    public sealed class LazyStack : IResolutionTrack
+    {
+        private readonly Stack<CardInstance> stackedCards = new();
+
+        public int Count => stackedCards.Count;
+
+        public void Enqueue(CardInstance card)
+        {
+            throw new NotImplementedException();
+        }
+
+        public void Resolve(CombatContext context)
+        {
+            throw new NotImplementedException();
+        }
+
+        public void ForceEvaluate(CombatContext context)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}