ship the side art as a cached stylesheet so cached loads paint in one frame

sideart.php

@@ -0,0 +1,10 @@
+<?php
+// The side art as a stylesheet (see inc/art.php). The URL carries ?v=, so it
+// can be cached for good.
+require_once __DIR__ . '/config.php';
+require_once __DIR__ . '/inc/art.php';
+
+[$css] = ansi_css_cached(__DIR__ . '/inc/art/sakura.ans'); // render (or fail) before the headers
+header('Content-Type: text/css; charset=utf-8');
+header('Cache-Control: public, max-age=31536000, immutable');
+readfile($css);