feat: demo显示听牌状态+可胡张数

引擎: MahjongRoom.GetTingTiles(player) 返回所有可胡的unique tile
Demo: 每回合后显示'听牌: X: 🀄听N张(tile1 tile2...) | Y: 未听...'
包含已胡/副露中的tile计数,兼容wildcard和258规则

示例: 听牌: AI-东: 🀄听 1张(中) | AI-南: 未听 | AI-西: 未听 | AI-北: 未听

Demo/Program.cs

@@ -174,10 +174,24 @@ else
             }
         }
 
+        // 听牌检测: 每回合后显示各玩家听牌状态
+        var tingInfo = new List<string>();
+        foreach (var p in room.State.AlivePlayers)
+        {
+            var tingTiles = room.GetTingTiles(p);
+            if (tingTiles.Count > 0)
+            {
+                var tileNames = tingTiles.Select(MahjongTile.ToString);
+                tingInfo.Add($"{p}: 🀄听 {tingTiles.Count}张({string.Join(" ", tileNames)})");
+            }
+            else
+                tingInfo.Add($"{p}: 未听");
+        }
+        Console.WriteLine($"  听牌: {string.Join(" | ", tingInfo)}");
+
         // Show current hands
         if (!room.IsFinished)
         {
-            // In human mode, show only opponent hands (human HUD shows their own)
             Console.WriteLine();
             if (humanMode)
             {