fix: code review — 修复4个问题

1. CardTracker.UnknownCount: 48→52 (硬编码修正)
2. IsmctsBot.GenerateDeck → 静态FullDeck池复用 (减少对象分配)
3. CardTracker: 删除3个死字段(_passStreak/_isNewRound/_bombCounts)
4. CardTracker.Update: 清理pass约束记录逻辑

验证: 100局0错误, 0.9s/局

PdkFriendServer/Logic/IsmctsBot.cs

@@ -295,7 +295,7 @@ namespace PdkFriendServer.Logic
             hands[nextPos - 1] = new List<TCardInfoPdkF>();
             hands[oppPos - 1] = new List<TCardInfoPdkF>();
 
-            var allCards = GenerateDeck();
+            var allCards = GetDeckCopy();
             var unknown = allCards.Where(c => !myHand.Any(h => h.ID == c.ID)).ToList();
 
             // 使用 CardTracker 进行约束采样
@@ -495,13 +495,29 @@ namespace PdkFriendServer.Logic
             return best;
         }
 
-        private static List<TCardInfoPdkF> GenerateDeck()
+        // 静态牌池：52张牌，只创建一次
+        private static readonly TCardInfoPdkF[] FullDeck;
+        static IsmctsBot()
         {
-            var d = new List<TCardInfoPdkF>(); int id = 1;
+            FullDeck = new TCardInfoPdkF[52];
+            int id = 1;
             foreach (int f in new[] { 1, 2, 3, 4 })
                 for (int n = 1; n <= 13; n++)
-                    d.Add(new TCardInfoPdkF { ID = (byte)id++, Flower = (byte)f, GameNum = (byte)(n == 1 ? 14 : n == 2 ? 16 : n), GameState = 1 });
-            return d;
+                    FullDeck[id - 1] = new TCardInfoPdkF
+                    {
+                        ID = (byte)id,
+                        Flower = (byte)f,
+                        GameNum = (byte)(n == 1 ? 14 : n == 2 ? 16 : n),
+                        GameState = 1
+                    };
+        }
+
+        private static List<TCardInfoPdkF> GetDeckCopy()
+        {
+            return FullDeck.Where(c => c.ID > 0).Select(c => new TCardInfoPdkF
+            {
+                ID = c.ID, Flower = c.Flower, GameNum = c.GameNum, GameState = 1
+            }).ToList();
         }
 
         private void Shuffle<T>(List<T> l) { for (int i = l.Count - 1; i > 0; i--) { int j = _rng.Next(i + 1); (l[i], l[j]) = (l[j], l[i]); } }