fix template consolidation: admin/head.php wraps public/head.php, footer.php wired to all public pages, remove duplicate font-family and body reset

templates/public/head.php

@@ -4,6 +4,7 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <title><?= htmlspecialchars($pageTitle ?? 'Posterg') ?></title>
+    <?php if (!empty($_adminHead)) { $ogTags = []; $metaDescription = ''; } ?>
     <?php if (!empty($metaDescription)): ?>
     <meta name="description" content="<?= htmlspecialchars($metaDescription) ?>">
     <?php endif; ?>