add wiring for offensive buffs

Assets/_Project/Scripts/Gameplay/BuffDefinition.cs

@@ -0,0 +1,24 @@
+// Assets/_Project/Scripts/Gameplay/BuffDefinition.cs
+using UnityEngine;
+using TD.Core;
+
+namespace TD.Gameplay
+{
+    /// <summary>
+    /// One possible buff that can be awarded to a player. Lives in a
+    /// <see cref="BuffCategory"/>'s pool and is drawn randomly on purchase.
+    /// </summary>
+    [CreateAssetMenu(fileName = "BuffDefinition", menuName = "TD/Buffs/Buff Definition")]
+    public class BuffDefinition : ScriptableObject
+    {
+        [Tooltip("Name shown in the buff menu and tooltip.")]
+        public string DisplayName;
+
+        [Tooltip("Which tower stat this buff multiplies.")]
+        public BuffStat Stat;
+
+        [Tooltip("Multiplicative factor applied to the stat. 1.25 = +25%.")]
+        [Min(1f)]
+        public float Multiplier = 1.25f;
+    }
+}