feat: AddMultiCardLeads 补全 — 三带二/四带二/四带三

引擎支持(GetOutCard已验证): DanZhang/DuiZi/SanDai2/ShunZi/LianDui/
  FeiJi/ZhaDan/SiDai2/SiDai3/FeijiDai2

AddMultiCardLeads 新增:
- 三带二: 三张相同 + 附带手牌最小的2张
- 四带二: 四张相同 + 附带2张 (优先四带三)

10局验证: DuiZi 54 | DanZhang 53 | ShunZi 16 | SanDai2 13 | SiDai 2
单张比例: 100% → 38%

PdkFriendServer/Logic/IsmctsBot.cs

@@ -315,62 +315,67 @@ namespace PdkFriendServer.Logic
         private static void AddMultiCardLeads(TCardInfoPdkF[] hand, int pos,
             List<(PlayOutCardPdkF play, bool isMulti)> candidates, ref int multiCount)
         {
-            // 获取炸弹
+            // 炸弹
             if (PokerLogic.GetPlayZhaDans(hand, out var bombs) && bombs != null)
-            {
                 foreach (var bomb in bombs)
-                {
-                    candidates.Add((new PlayOutCardPdkF
-                    {
-                        Pos = (byte)pos, GameNum = bomb[0].GameNum,
-                        Ids = bomb.Select(c => c.ID).ToArray(),
-                        Type = CardType1.None
-                    }, true));
-                    multiCount++;
-                }
-            }
+                    AddCandidate(bomb, pos, candidates, ref multiCount);
 
-            // 获取对子（2张相同）
-            var pairs = GetMultiGroups(hand, 2);
-            foreach (var pair in pairs)
-            {
-                candidates.Add((new PlayOutCardPdkF
-                {
-                    Pos = (byte)pos, GameNum = pair[0].GameNum,
-                    Ids = pair.Select(c => c.ID).ToArray(),
-                    Type = CardType1.None
-                }, true));
-                multiCount++;
-            }
+            // 对子（2张相同）
+            foreach (var pair in GetMultiGroups(hand, 2))
+                AddCandidate(pair, pos, candidates, ref multiCount);
 
-            // 获取三张
+            // 三张 / 三带二
             var triples = GetMultiGroups(hand, 3);
             foreach (var t in triples)
             {
-                candidates.Add((new PlayOutCardPdkF
+                // 三带二: 三张 + 附带最小的两张其他牌
+                var remainder = hand.Where(c => c.GameNum != t[0].GameNum).OrderBy(c => c.GameNum).ToList();
+                if (remainder.Count >= 2)
                 {
-                    Pos = (byte)pos, GameNum = t[0].GameNum,
-                    Ids = t.Select(c => c.ID).ToArray(),
-                    Type = CardType1.None
-                }, true));
-                multiCount++;
-            }
-
-            // 获取顺子（≥5 张连续）
-            var straights = PokerLogic.GetShunZi(hand);
-            if (straights != null)
-            {
-                foreach (var s in straights)
+                    var sd2 = t.Concat(remainder.Take(2)).ToList();
+                    AddCandidate(sd2, pos, candidates, ref multiCount);
+                }
+                else
                 {
-                    candidates.Add((new PlayOutCardPdkF
-                    {
-                        Pos = (byte)pos, GameNum = s[0].GameNum,
-                        Ids = s.Select(c => c.ID).ToArray(),
-                        Type = CardType1.None
-                    }, true));
-                    multiCount++;
+                    AddCandidate(t, pos, candidates, ref multiCount); // 手牌不够带，纯三张
                 }
             }
+
+            // 四带二 / 四带三
+            var quads = GetMultiGroups(hand, 4);
+            foreach (var q in quads)
+            {
+                var remainder = hand.Where(c => c.GameNum != q[0].GameNum).OrderBy(c => c.GameNum).ToList();
+                if (remainder.Count >= 3)
+                {
+                    var sd3 = q.Concat(remainder.Take(3)).ToList();
+                    AddCandidate(sd3, pos, candidates, ref multiCount);
+                }
+                else if (remainder.Count >= 2)
+                {
+                    var sd2 = q.Concat(remainder.Take(2)).ToList();
+                    AddCandidate(sd2, pos, candidates, ref multiCount);
+                }
+                // else: 炸弹已在上面处理
+            }
+
+            // 顺子（≥5 张连续）
+            var straights = PokerLogic.GetShunZi(hand);
+            if (straights != null)
+                foreach (var s in straights)
+                    AddCandidate(s, pos, candidates, ref multiCount);
+        }
+
+        private static void AddCandidate(List<TCardInfoPdkF> cards, int pos,
+            List<(PlayOutCardPdkF play, bool isMulti)> candidates, ref int multiCount)
+        {
+            candidates.Add((new PlayOutCardPdkF
+            {
+                Pos = (byte)pos, GameNum = cards[0].GameNum,
+                Ids = cards.Select(c => c.ID).ToArray(),
+                Type = CardType1.None
+            }, true));
+            multiCount++;
         }
 
         /// <summary>获取指定数量的同面值组合（对子=2，三张=3）</summary>