Mobile: center pinned post, pagination fixes, minor layout tweaks

- First (pinned) post on mobile: title and image centered
- Pagination: restored page counter on mobile, buttons above footer
- Typography and layout minor improvements

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

layouts/shortcodes/gallery.html

@@ -41,5 +41,5 @@ Documentation and licence at https://github.com/liwenyip/hugo-easy-gallery/
 	{{- end }}
 </div>
 
-<!-- Добавляем кнопку "вернуться в начало" для галереи -->
-{{ partial "back-to-top.html" . }}
+<!-- Ленивая загрузка фонов -->
+<script src="{{ "js/gallery-lazy.js" | relURL }}" defer></script>