feat: add file viewer to welcome page

Author: Mauve Signweaver

app/pages/welcome.html

@@ -52,6 +52,7 @@ <h1>
 <p>
 	<a href="hyper://agregore.mauve.moe/explore">Explore</a>
 	<a href="hyper://agregore.mauve.moe/apps/scratchpad.html">Build</a>
+	<a href="hyper://agregore.mauve.moe/apps/fileviewer.html">FileViewer</a>
 </p>
 <p>
 	<a href="hyper://agregore.mauve.moe/">Main Website</a>