Implement basic structure for combat system and refactor code

Assets/Scripts/Combat/CardInstance.cs

@@ -0,0 +1,20 @@
+using KernelPanic.Data;
+
+namespace KernelPanic.Combat
+{
+    /// <summary>
+    /// Represents one runtime card and its per-combat mutable state.
+    /// </summary>
+    public sealed class CardInstance
+    {
+        public CardInstance(CardDefinition definition)
+        {
+            Definition = definition;
+        }
+
+        public CardDefinition Definition { get; }
+        public int TemporaryCostDelta { get; set; }
+        public bool IsBroken { get; set; }
+        public bool IsLocked { get; set; }
+    }
+}