FrankenPHP's unicode case-folding length expansion causes incorrect split_path index (SCRIPT_NAME/PATH_INFO confusion) in FrankenPHP

Summary FrankenPHP’s CGI path splitting logic improperly handles Unicode characters during case conversion. The logic computes the split index for finding .php on a lowercased copy of the request path but applies that byte index to the original path. Because strings.ToLower in Go can increase the...