Add lines of code badge to README

Author: kojix2

README.md

@@ -1,6 +1,7 @@
 # GPScan Viewer
 
 [![Build](https://github.com/kojix2/gpscan_viewer/actions/workflows/build.yml/badge.svg)](https://github.com/kojix2/gpscan_viewer/actions/workflows/build.yml)
+[![Lines of Code](https://img.shields.io/endpoint?url=https%3A%2F%2Ftokei.kojix2.net%2Fbadge%2Fgithub%2Fkojix2%2Fgpscan_viewer%2Flines)](https://tokei.kojix2.net/github/kojix2/gpscan_viewer)
 
 ![Screenshot](https://raw.githubusercontent.com/kojix2/gpscan_viewer/screenshot/root.png)
 
@@ -89,4 +90,4 @@ Copyright (C) 2005-2025, Erwin Bonsma.
 This project was developed primarily with the assistance of AI tools.
 
 GrandPerspective is distributed under the GNU General Public License (GPL), and this project is
-distributed under GPL-2.0-or-later accordingly.
+distributed under GPL-2.0-or-later accordingly.