start of draft option upgrades

Assets/_Project/Scripts/Gameplay/PlayerSpellLoadout.cs

@@ -139,6 +139,28 @@ namespace TD.Gameplay
             return true;
         }
 
+        /// <summary>
+        /// Server-only: replaces a previously granted spell with a different one (an upgrade
+        /// pick), in place — the upgraded spell keeps the base spell's hotkey slot and starts
+        /// off cooldown. No-op if the old spell isn't currently granted or the new one already
+        /// is. Returns true if the swap happened.
+        /// </summary>
+        public bool ServerUpgradeSpell(BuilderSpellKind oldKind, BuilderSpellKind newKind)
+        {
+            if (!IsServer) return false;
+            if (PlayerHasSpell(newKind)) return false;
+
+            for (int i = 0; i < spells.Count; i++)
+            {
+                if (spells[i].Kind == oldKind)
+                {
+                    spells[i] = SpellSlot.CreateReady(newKind);
+                    return true;
+                }
+            }
+            return false;
+        }
+
         // ----- Cast RPC -----------------------------------------------------
 
         /// <summary>