Extract pagination into templates/partials/pagination.php

The pagination nav was duplicated between public/index.php and public/search.php
with structural differences: index.php used string concatenation for query params
and had first/last-page buttons (« »); search.php used http_build_query but had
only prev/next (‹ ›) and a flat <span> rather than a <ul>/<li> structure.

- Add templates/partials/pagination.php: accepts $page, $totalPages, $baseParams[]
  (any array of query params to preserve); builds URLs with http_build_query;
  renders a semantic <nav>/<ul>/<li> block with first/prev/info/next/last buttons,
  correct aria-disabled + tabindex on disabled links, and aria-label on each button.
  Returns immediately (no output) when $totalPages <= 1.

- Replace inline pagination block in index.php with:
    $baseParams = array_filter(['year' => $year]);
    include pagination.php

- Replace inline pagination block in search.php with:
    $baseParams = array_diff_key($_GET, ['page' => '']);
    include pagination.php
  This also upgrades search.php to the full first/last button set it was missing.

Both callers verified with php -l. No functional change to existing behaviour.

public/search.php

@@ -179,19 +179,11 @@ $bodyClass = 'search-body';
                 <?php endforeach; ?>
             </ul>
 
-            <?php if ($totalPages > 1): ?>
-            <nav class="pagination-wrap" aria-label="Pagination">
-                <a href="?<?= http_build_query(array_merge($_GET, ['page' => max(1, $page - 1)])) ?>"
-                   class="pagination-btn<?= $page <= 1 ? ' disabled' : '' ?>"
-                   <?= $page <= 1 ? 'aria-disabled="true" tabindex="-1"' : '' ?>
-                   aria-label="Page précédente">‹</a>
-                <span class="pagination-info" aria-current="page"><?= $page ?> / <?= $totalPages ?></span>
-                <a href="?<?= http_build_query(array_merge($_GET, ['page' => min($totalPages, $page + 1)])) ?>"
-                   class="pagination-btn<?= $page >= $totalPages ? ' disabled' : '' ?>"
-                   <?= $page >= $totalPages ? 'aria-disabled="true" tabindex="-1"' : '' ?>
-                   aria-label="Page suivante">›</a>
-            </nav>
-            <?php endif; ?>
+            <?php
+            // Preserve all active search/filter params (strip 'page' — injected by partial)
+            $baseParams = array_diff_key($_GET, ['page' => '']);
+            include APP_ROOT . '/templates/partials/pagination.php';
+            ?>
 
             <?php else: ?>
             <p class="search-empty">Aucun résultat pour cette recherche.</p>