feat: add PGN4Web block support and integrate chess game replay features

Implemented a new PGN4Web block with a PHP snippet for game replay functionality. Updated blueprints with PGN-specific fields, modified layout and blockpage templates, and included necessary JavaScript and assets for interactive chess game rendering. Enhanced memorial page with replayable game content.

site/templates/blockpage.php

@@ -20,13 +20,12 @@ function fenToBoard($fen) {
     }
 
     return $board;
-} ?>
-
+}?>
 
 <?php
 snippet('layout', slots: true) ?>
 
-<?= $page->blocks()->toBlocks() ?>
+    <?= $page->blocks()->toBlocks() ?>
 
 <?php
-endsnippet() ?>
+endsnippet() ?>