fix: 消除 CS8604 warning (DslLoader f.Condition nullability)

LINQ Where 过滤了空值但编译器不跟踪 → 加 null-forgiving operator

RuleEngine/Dsl/DslLoader.cs

@@ -81,7 +81,7 @@ public class CapabilityRegistry
         var knownConditions = new HashSet<string> { "hand_contains_wildcard", "can_win_tumo_and_fan_ge_8", "can_win_and_fan_ge_8" };
         foreach (var f in rules.FanTypes.Where(f => !string.IsNullOrEmpty(f.Condition)))
         {
-            if (!knownConditions.Contains(f.Condition))
+            if (!knownConditions.Contains(f.Condition!))
                 warnings.Add($"番型「{f.Name}」条件「{f.Condition}」引擎无法评估→番型永不触发");
         }