fix: 番型互斥从未应用 + FanValue兜底乱给分 + 白名单过滤

Root cause:
1. ApplyFanExclusions定义但从未被调用 → 互斥(清一色⊃缺一门)形同虚设
2. FanValue中 _=>1 兜底 → '缺一门''平胡'等不在DSL的番型也被+1分
3. IdentifyFans返回所有结构模式 → 与DSL配置不一致

修复:
- CheckWin五处IdentifyFans调用后加ApplyFanExclusions
- FanValue去掉_=>1,改为只认DSL配置+硬编码知名番型
- IdentifyFans末尾白名单过滤:只返回DSL或知名番型
- PhaseMachine.GetFanValue同步更新
- ScoreEngine: 不在DSL的番型→0分

RuleEngine/Phase/PhaseMachine.cs

@@ -102,14 +102,11 @@ public class MahjongPhaseMachine
 
     private int GetFanValue(string fanName)
     {
-        // Simple lookup — full implementation would read from DSL
         return fanName switch
         {
-            "清一色" => 4,
-            "对对胡" => 2,
-            "暗七对" => 4,
-            "带幺九" => 2,
-            _ => 1
+            "清一色" => 24, "混一色" => 6, "对对胡" => 2,
+            "暗七对" => 8, "七对" => 8, "带幺九" => 2, "十三幺" => 88,
+            _ => 0
         };
     }