fix: Code Review — CheckTing完全断裂 + 座位顺序 + FanValue硬编码

🔴 Critical: CheckTing逻辑完全错误
- 旧: testHand.RemoveAt(i) → 13张 → CheckWin守卫拒绝(≠14) → 听牌检测永远false
- 新: 遍历所有可摸牌(27-34种), CheckWin(hand, newTile:tile) → 正确检测听牌
- 新增2个听牌测试

🟡 Medium: HandleDiscardReactions 同优先级顺序
- 旧: OrderByDescending取第一个，不保证座位顺序
- 新: 按座位顺序遍历，高优先级覆盖，同优先级先到先得

🟡 Medium: ScoreEngine.FanValue 硬编码番值
- 旧: switch expression 仅5种番型
- 新: 优先从 _fanConfig(DSL)读取，fallback到硬编码

🟢 Low: 删除硬编码的258将事件(非武汉也输出)

RuleEngine.Tests/CoreTests.cs

@@ -349,4 +349,36 @@ public class MeldsSolverTests
         var fans = _solver.IdentifyFans(result!);
         Assert.Contains("断幺九", fans);
     }
+
+    // === 听牌检查 ===
+    [Fact]
+    public void 听牌_缺一张__ShouldDetectTing()
+    {
+        // 13 tiles, needs 9万 to complete 123万 456万 789万 111条 99条
+        var hand = new List<int> { 1, 2, 3, 4, 5, 6, 7, 8, 11, 11, 11, 19, 19 };
+        var allTiles = MahjongTile.AllTiles(false, false);
+        bool hasTing = false;
+        foreach (var tile in allTiles)
+        {
+            if (hand.Count(t => t == tile) >= 4) continue;
+            var r = _solver.CheckWin(hand, newTile: tile);
+            if (r != null && r.IsWin) { hasTing = true; break; }
+        }
+        Assert.True(hasTing, "13张听牌应检测到至少一张能胡的牌");
+    }
+
+    [Fact]
+    public void 听牌_乱牌__ShouldNotDetectTing()
+    {
+        var hand = new List<int> { 1, 3, 5, 7, 9, 11, 13, 15, 21, 23, 25, 31, 33 };
+        var allTiles = MahjongTile.AllTiles(false, false);
+        bool hasTing = false;
+        foreach (var tile in allTiles)
+        {
+            if (hand.Count(t => t == tile) >= 4) continue;
+            var r = _solver.CheckWin(hand, newTile: tile);
+            if (r != null && r.IsWin) { hasTing = true; break; }
+        }
+        Assert.False(hasTing, "乱牌不应检测到听牌");
+    }
 }