add wiring for offensive buffs

Assets/_Project/Scripts/Gameplay/BuffCategory.cs

@@ -0,0 +1,23 @@
+// Assets/_Project/Scripts/Gameplay/BuffCategory.cs
+using UnityEngine;
+
+namespace TD.Gameplay
+{
+    /// <summary>
+    /// A purchasable category of buffs. The player pays <see cref="Cost"/> gold
+    /// and receives a randomly chosen <see cref="BuffDefinition"/> from <see cref="Pool"/>.
+    /// </summary>
+    [CreateAssetMenu(fileName = "BuffCategory", menuName = "TD/Buffs/Buff Category")]
+    public class BuffCategory : ScriptableObject
+    {
+        [Tooltip("Name shown on the buff menu purchase button.")]
+        public string DisplayName;
+
+        [Tooltip("Gold cost to purchase one random buff from this category.")]
+        [Min(0)]
+        public int Cost;
+
+        [Tooltip("Set of buffs the player can receive. One is chosen uniformly at random.")]
+        public BuffDefinition[] Pool;
+    }
+}