ui: add experimental speculation rules

packages/ui-default/pages/contest.page.ts

@@ -1,7 +1,7 @@
 import { formatSeconds } from '@hydrooj/utils/lib/common';
 import NProgress from 'nprogress';
 import { NamedPage } from 'vj/misc/Page';
-import { tpl } from 'vj/utils';
+import { addSpeculationRules, tpl } from 'vj/utils';
 
 const contestTimer = $(tpl`<pre class="contest-timer" style="display:none"></pre>`);
 contestTimer.appendTo(document.body);
@@ -21,4 +21,15 @@ export default new NamedPage(['contest_detail', 'contest_problemlist', 'contest_
   NProgress.start();
   updateProgress();
   setInterval(updateProgress, 1000);
+
+  addSpeculationRules({
+    prerender: [{
+      'where': {
+        'or': [
+          { 'href_matches': '/p/*' },
+          { 'href_matches': '/d/*/p/*' },
+        ],
+      },
+    }],
+  });
 });