feat: Implement secure authentication module and integrate session management across multiple files

tools.php

@@ -4,6 +4,9 @@
  * Technische inspectie en utilities voor serverbeheer, DNS en debugging.
  */
 
+require_once __DIR__ . '/auth.php';
+require_auth();
+
 // PHP Backend AJAX handler
 if (isset($_GET['action'])) {
     header('Content-Type: application/json; charset=utf-8');
@@ -154,9 +157,10 @@ $loadDisplay = $load ? implode(' / ', array_map(function($v) { return round($v,
             </div>
             <div class="nav-status">
                 <button class="btn btn-secondary btn-sm theme-btn" onclick="toggleTheme()">🌙 Thema</button>
+                <a href="logout.php" class="btn btn-secondary btn-sm" style="color: #f87171;" title="Veilig uitloggen">🚪 Uitloggen</a>
                 <span class="nav-badge">
                     <span class="pulse-dot"></span>
-                    Git Live
+                    server.webenpcstudio.nl
                 </span>
             </div>
         </nav>