fix: 人类玩家显示摸到的牌 (LastDrawnTile + 箭头高亮)

- GameState新增LastDrawnTile字段
- StepTurn摸牌时记录LastDrawnTile
- HumanMahjongPlayer显示'刚刚摸到:X'并用→←箭头标记新牌
- 庄家首轮LastDrawnTile清空

RuleEngine/AI/HumanMahjongPlayer.cs

@@ -21,13 +21,22 @@ public class HumanMahjongPlayer
         var hand = state.Hands.GetValueOrDefault(Name, new List<int>());
         var sorted = hand.OrderBy(t => t).ToList();
 
+        // Highlight last drawn tile
+        int? drawnTile = state.LastDrawnTile;
+        int drawnIdx = drawnTile.HasValue ? sorted.IndexOf(drawnTile.Value) : -1;
+
         while (true)
         {
             Console.WriteLine();
             Console.WriteLine($"=== {Name} 的回合 ===");
+            if (drawnTile.HasValue && drawnIdx >= 0)
+                Console.WriteLine($"  🀫 刚刚摸到: {MahjongTile.ToString(drawnTile.Value)}");
             Console.WriteLine($"手牌 ({hand.Count}张):");
             for (int i = 0; i < sorted.Count; i++)
-                Console.WriteLine($"  [{i + 1}] {MahjongTile.ToString(sorted[i])}");
+            {
+                bool isDrawn = (i == drawnIdx);
+                Console.WriteLine($"  [{i + 1}] {(isDrawn ? "→ " : "  ")}{MahjongTile.ToString(sorted[i])}{(isDrawn ? " ← 新摸" : "")}");
+            }
             Console.WriteLine();
 
             // Show available actions