admin/index.php: add server-side pagination (25/page)

- Add Database::getThesesListCount(array $filters) — runs the same WHERE
  clauses as getThesesList() but with COUNT(DISTINCT t.id); used to compute
  total pages without loading all rows.
- Extend Database::getThesesList() with $limit/$offset parameters; when
  $limit > 0 appends LIMIT/OFFSET and re-binds positional params individually
  to avoid the PDO mixed-style restriction.
- Fix getThesesList() SELECT: add LEFT JOIN access_types + at.name as
  access_type — the column was referenced in the template but never fetched.
- Wire admin/index.php: read ?page=, compute $totalPages/$offset, pass
  $perPage=25 + $offset to getThesesList(); include pagination.php partial
  below the table with filter-preserving $baseParams.
- Add result-count line (<p class="admin-list-meta">) showing "X–Y sur Z TFE"
  when multiple pages exist.
- Add .admin-body .pagination-wrap / .pagination-btn / .pagination-info styles
  to admin.css (scoped to .admin-body to avoid colliding with public pages).

public/admin/index.php

@@ -21,7 +21,14 @@ try {
     if ($yearFilter)        $filters['year']        = $yearFilter;
     if ($orientationFilter) $filters['orientation'] = $orientationFilter;
 
-    $theses       = $db->getThesesList($filters);
+    $perPage    = 25;
+    $page       = isset($_GET['page']) ? max(1, intval($_GET['page'])) : 1;
+    $totalCount = $db->getThesesListCount($filters);
+    $totalPages = $totalCount > 0 ? (int) ceil($totalCount / $perPage) : 1;
+    $page       = min($page, $totalPages);
+    $offset     = ($page - 1) * $perPage;
+
+    $theses       = $db->getThesesList($filters, $perPage, $offset);
     $stats        = $db->getThesesStats();
     $years        = $db->getAllYears();
     $orientations = $db->getAllOrientations();
@@ -74,14 +81,14 @@ document.addEventListener('DOMContentLoaded', () => {
     <aside role="status" class="admin-maintenance-bar <?= $maintenanceOn ? 'admin-maintenance-bar--active' : '' ?>" aria-label="Statut du site">
         <?php if ($maintenanceOn): ?>
             <span>⚠ Mode maintenance <strong>activé</strong> — le site public est inaccessible.</span>
-            <form method="post" action="actions/maintenance.php" style="display:inline;">
+            <form method="post" action="actions/maintenance.php">
                 <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
                 <input type="hidden" name="action" value="disable_maintenance">
                 <button type="submit" class="admin-btn admin-btn--sm">Désactiver la maintenance</button>
             </form>
         <?php else: ?>
             <span>Site public : <strong>en ligne</strong></span>
-            <form method="post" action="actions/maintenance.php" style="display:inline;">
+            <form method="post" action="actions/maintenance.php">
                 <input type="hidden" name="csrf_token" value="<?= htmlspecialchars($_SESSION['csrf_token']) ?>">
                 <input type="hidden" name="action" value="enable_maintenance">
                 <button type="submit" class="admin-btn admin-btn--sm admin-btn--warning"
@@ -150,8 +157,19 @@ document.addEventListener('DOMContentLoaded', () => {
 
     <!-- Table -->
     <?php if (empty($theses)): ?>
-        <p style="color:var(--text-secondary);padding:1rem 0;">Aucun TFE trouvé.</p>
+        <p class="admin-empty">Aucun TFE trouvé.</p>
     <?php else: ?>
+    <p class="admin-list-meta">
+        <?php
+        $from = $offset + 1;
+        $to   = min($offset + $perPage, $totalCount);
+        if ($totalPages > 1) {
+            echo "$from–$to sur $totalCount TFE";
+        } else {
+            echo "$totalCount TFE";
+        }
+        ?>
+    </p>
     <table>
         <thead>
             <tr>
@@ -170,7 +188,7 @@ document.addEventListener('DOMContentLoaded', () => {
             <?php foreach ($theses as $thesis): ?>
             <tr>
                 <td><input type="checkbox" name="selected_theses[]" value="<?= $thesis['id'] ?>"></td>
-                <td style="color:var(--text-secondary);font-size:.8rem;"><?= htmlspecialchars($thesis['identifier'] ?? $thesis['id']) ?></td>
+                <td class="admin-table-id"><?= htmlspecialchars($thesis['identifier'] ?? $thesis['id']) ?></td>
                 <td>
                     <div class="thesis-title"><?= htmlspecialchars($thesis['title']) ?></div>
                     <?php if ($thesis['subtitle']): ?>
@@ -210,6 +228,15 @@ document.addEventListener('DOMContentLoaded', () => {
         </tbody>
     </table>
     <?php endif; ?>
+
+    <?php
+    $baseParams = array_filter([
+        'search'      => $searchQuery,
+        'year'        => $yearFilter ?: '',
+        'orientation' => $orientationFilter ?: '',
+    ]);
+    include APP_ROOT . '/templates/partials/pagination.php';
+    ?>
 </main>
 
 <?php require_once APP_ROOT . '/templates/admin/footer.php'; ?>