feat: admin audit logging across all admin actions

- AdminLogger: JSON-lines → /var/log/xamxam.log (prod) / storage/logs/admin.log (dev)
  + best-effort DB mirror to admin_audit_log table
- DB: admin_audit_log table, share_links.is_archived column
- ShareLink: archive() replaces delete(), toggleActive() returns new state,
  listActive()/listArchived() split, validateLink blocks archived slugs
- All action handlers wired: publish, unpublish, visibility, delete, csv/db export,
  tfe add/edit, tags, pages, apropos, form-help, access-request, maintenance,
  settings (formulaire toggles, objet types, smtp update), smtp-test
- acces.php: archive button replaces delete; collapsible archived links section
- setup-server.sh: provision /var/log/xamxam.log (www-data:xamxam 640)

app/public/admin/actions/edit.php

@@ -25,6 +25,7 @@ if ($thesisId <= 0) {
 }
 
 require_once APP_ROOT . '/src/Controllers/ThesisEditController.php';
+require_once APP_ROOT . '/src/AdminLogger.php';
 
 try {
     $ctrl = ThesisEditController::create();
@@ -33,6 +34,8 @@ try {
     // Regenerate CSRF token after successful save
     $_SESSION['csrf_token'] = bin2hex(random_bytes(32));
 
+    AdminLogger::make()->logEdit($thesisId, $_POST['titre'] ?? $_POST['title'] ?? '');
+
     App::flash('success', "TFE mis à jour avec succès!");
     header('Location: ../edit.php?id=' . $thesisId);
     exit();