refactor(enemy): Boss 选招与战利品掉落改用 WeightedPick;删除零调用的 SelectWeightedSkill 死代码

Assets/_Game/Scripts/Enemies/Boss/BossSkillExecutor.cs

@@ -127,37 +127,6 @@ namespace BaseGames.Boss
         /// <summary>Inspector 中注册的全部技能 SO（只读）。</summary>
         public BossSkillSO[] Skills => _skills;
 
-        /// <summary>
-        /// 从候选技能列表中按 weight 加权随机选择一个技能。
-        /// 权重为 0 的技能不参与选择；所有候选权重均为 0 时返回 null。
-        /// </summary>
-        public BossSkillSO SelectWeightedSkill(System.Collections.Generic.IList<BossSkillSO> candidates)
-        {
-            if (candidates == null || candidates.Count == 0) return null;
-
-            float totalWeight = 0f;
-            for (int i = 0; i < candidates.Count; i++)
-            {
-                var s = candidates[i];
-                if (s != null && s.weight > 0f) totalWeight += s.weight;
-            }
-            if (totalWeight <= 0f) return null;
-
-            float roll = UnityEngine.Random.value * totalWeight;
-            float acc  = 0f;
-            for (int i = 0; i < candidates.Count; i++)
-            {
-                var s = candidates[i];
-                if (s == null || s.weight <= 0f) continue;
-                acc += s.weight;
-                if (roll <= acc) return s;
-            }
-            // 浮点精度兜底：返回最后一个有效候选
-            for (int i = candidates.Count - 1; i >= 0; i--)
-                if (candidates[i]?.weight > 0f) return candidates[i];
-            return null;
-        }
-
         /// <summary>
         /// 执行一个 Boss 技能。若当前正在执行或技能冷却未就绪则返回。
         /// </summary>