Add clarifying comment about backward compatibility for path normalization

Co-authored-by: marcpopMSFT <[email protected]>

Author: Copilot

src/Cli/dotnet/Commands/Run/RunCommand.cs

@@ -529,8 +529,10 @@ internal static void ThrowUnableToRunError(ProjectInstance project)
             projectFileOrDirectoryPath = Directory.GetCurrentDirectory();
         }
 
-        // Normalize path separators to handle Windows-style paths on non-Windows platforms
-        // First convert backslashes to forward slashes on non-Windows, then get the full path
+        // Normalize path separators to handle Windows-style paths on non-Windows platforms.
+        // This is supported for backward compatibility in 'dotnet run' only, not for all CLI commands.
+        // Converting backslashes to forward slashes allows PowerShell scripts using Windows-style paths
+        // to work cross-platform, maintaining compatibility with .NET 9 behavior.
         if (Path.DirectorySeparatorChar != '\\')
         {
             projectFileOrDirectoryPath = projectFileOrDirectoryPath.Replace('\\', '/');