fix: validate actualLabels length in DI detector

Author: ooples

src/Interpretability/DisparateImpactBiasDetector.cs

@@ -93,6 +93,11 @@ protected override BiasDetectionResult<T> GetBiasDetectionResult(
             // If labels are available, compute TPR/FPR/Precision per group and Equal Opportunity difference.
             if (actualLabels != null)
             {
+                if (actualLabels.Length != predictions.Length)
+                {
+                    throw new ArgumentException("Actual labels vector must have the same length as predictions.", nameof(actualLabels));
+                }
+
                 var groupTruePositiveRates = new Dictionary<string, T>();
                 var groupFalsePositiveRates = new Dictionary<string, T>();
                 var groupPrecisions = new Dictionary<string, T>();