fix negative index

ConfusedPolarBear.Plugin.IntroSkipper/Analyzers/ChapterAnalyzer.cs

@@ -113,7 +113,7 @@ public ChapterAnalyzer(ILogger<ChapterAnalyzer> logger)
             });
 
             // Check all chapters in reverse order, skipping the virtual chapter
-            for (int i = chapters.Count - 2; i >= 0; i--)
+            for (int i = chapters.Count - 2; i > 0; i--)
             {
                 var current = chapters[i];
                 var previous = chapters[i - 1];