Add liked videos gallery page

YouTube-style grid (2-4 columns) with thumbnail, views, subscribers and
outlier score, sortable. Link to it from the swipe app.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

index.html

@@ -187,6 +187,7 @@
   <div class="top-right">
     <button id="exportBtn" class="pill primary" disabled>Скачать ♥ <span id="exportCount">0</span></button>
     <button id="newFileBtn" class="pill hidden" title="Загрузить другой файл">Файл…</button>
+    <a class="pill" href="liked.html" title="Открыть галерею понравившихся" style="text-decoration:none">Галерея</a>
   </div>
 </header>