fix: DSL命名不一致 — camelCase→underscore_case (UnderscoredNamingConvention)

DSL YAML字段includeHonors/includeFlowers/wildcardCount等使用了camelCase,
但DslLoader配置了UnderscoredNamingConvention(期望include_honors)。
导致所有DSL的deck配置(字牌/花牌/wildcard)从未生效:
- 武汉: 108张(只有数牌) → 现140张(136+4wildcard)
- 国标: 108张 → 现144张(+花+字)
- 广东: 108张 → 现136张(+花+字)

修复: 4个YAML文件统一改为underscore_case

RuleEngine.Tests/MahjongRoomIntegrationTests.cs

@@ -55,9 +55,8 @@ public class MahjongRoomIntegrationTests
         room.Deal();
 
         int totalTiles = room.State.Hands.Sum(h => h.Value.Count) + room.State.Deck.Count;
-        // NOTE: UnderscoredNamingConvention doesn't map includeHonors/WildcardCount
-        // So deck uses defaults (108 numbered). Known issue — fix when switching naming policy.
-        Assert.Equal(108, totalTiles);
+        // 136 tiles + 4 wildcards = 140
+        Assert.Equal(140, totalTiles);
     }
 
     // === Turn flow ===