feat: afterMin牌效率加权 — 出牌后手牌结构改善→加分

- beforeMin = 当前手牌最小步数
- afterMin < beforeMin → +12% × improvement率
- afterMin > beforeMin 且多牌 → -3% (打散手牌惩罚)
- 效果: 单张-1.2%, 三带二+0.9%, 飞机×3, 锁手+2次

PdkFriendServer/Logic/IsmctsBot.cs

@@ -169,6 +169,25 @@ namespace PdkFriendServer.Logic
                     }
                 }
 
+                // 4.5. afterMin 牌效率加权
+                int beforeMin = HandOptimizer.MinPlays(hand);
+                for (int i = 0; i < scoredCandidates.Count; i++)
+                {
+                    var (p, wr, am, m) = scoredCandidates[i];
+                    if (am < beforeMin)
+                    {
+                        // 出牌后手牌结构变好 → 加权
+                        double improvement = (double)(beforeMin - am) / beforeMin;
+                        wr += improvement * 0.12; // 最多 +12% 当 minPlays 减半
+                    }
+                    else if (am > beforeMin && m)
+                    {
+                        // 多牌出牌反而把手牌打散了 → 惩罚
+                        wr -= 0.03;
+                    }
+                    scoredCandidates[i] = (p, wr, am, m);
+                }
+
                 // 5. 炸弹感知加权
                 int bombsOutside = _tracker.BombsOutside(hand);