add chaptify link

Author: zuzhi

themes/pico/html/base.html

@@ -28,6 +28,7 @@ <h4>
                 <a href="/archives.html">archives</a>
                 <a href="/til.html">til</a>
                 <a href="https://progress.huzuzhi.com">progress</a>
+                <a href="https://chaptify.vercel.app" target="_blank">chaptify</a>
                 <a href="https://github.com/zuzhi">github</a>
                 <a href="https://x.com/huzuzhi">x</a>
             </h4>