add wiring for offensive buffs

Assets/_Project/Scripts/Gameplay/ActiveBuff.cs

@@ -0,0 +1,61 @@
+// Assets/_Project/Scripts/Gameplay/ActiveBuff.cs
+using System;
+using Unity.Collections;
+using Unity.Netcode;
+using TD.Core;
+
+namespace TD.Gameplay
+{
+    /// <summary>
+    /// One buff currently held by a player. Stored in
+    /// <see cref="PlayerBuffManager"/>'s NetworkList so all peers see the same set.
+    /// </summary>
+    /// <remarks>
+    /// <para><b>IEquatable.</b> NGO's NetworkList indexer setter short-circuits when
+    /// Equals returns true, silently dropping the write. Every mutable field
+    /// (only <see cref="IsActive"/>) is included in the comparison so toggling a
+    /// buff correctly propagates to clients.</para>
+    /// </remarks>
+    public struct ActiveBuff : INetworkSerializable, IEquatable<ActiveBuff>
+    {
+        /// <summary>Which tower stat this buff multiplies.</summary>
+        public BuffStat Stat;
+
+        /// <summary>Multiplicative factor, e.g. 1.25 for +25%.</summary>
+        public float Multiplier;
+
+        /// <summary>
+        /// False when disabled (e.g. by an enemy ability). Excluded from
+        /// <see cref="PlayerBuffManager.GetMultiplier"/> while false.
+        /// </summary>
+        public bool IsActive;
+
+        /// <summary>Human-readable name for the HUD buff list.</summary>
+        public FixedString64Bytes DisplayName;
+
+        // ----- INetworkSerializable ---------------------------------------
+
+        public void NetworkSerialize<T>(BufferSerializer<T> serializer) where T : IReaderWriter
+        {
+            byte statByte = (byte)Stat;
+            serializer.SerializeValue(ref statByte);
+            Stat = (BuffStat)statByte;
+
+            serializer.SerializeValue(ref Multiplier);
+            serializer.SerializeValue(ref IsActive);
+            serializer.SerializeValue(ref DisplayName);
+        }
+
+        // ----- IEquatable -------------------------------------------------
+
+        public bool Equals(ActiveBuff other)
+            => Stat == other.Stat
+            && Multiplier == other.Multiplier
+            && IsActive == other.IsActive
+            && DisplayName == other.DisplayName;
+
+        public override bool Equals(object obj) => obj is ActiveBuff other && Equals(other);
+
+        public override int GetHashCode() => HashCode.Combine((int)Stat, Multiplier, IsActive);
+    }
+}