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

lab.php

@@ -4,6 +4,9 @@
  * Diepgaande diagnostische suite voor CPU, NVMe Disk I/O, RAM en HTTP Concurrency.
  */
 
+require_once __DIR__ . '/auth.php';
+require_auth();
+
 // Helper functies voor benchmarks
 function benchmarkCPU() {
     $start = microtime(true);
@@ -387,6 +390,7 @@ $serverSoftware = $_SERVER['SERVER_SOFTWARE'] ?? 'Apache / Nginx';
                 <button class="btn btn-secondary btn-sm" id="sound-btn" onclick="toggleAudio()" title="Schakel geluid in/uit">
                     <span id="sound-icon">🔈</span> Geluid: <span id="sound-status">Uit</span>
                 </button>
+                <a href="logout.php" class="btn btn-secondary btn-sm" style="color: #f87171;" title="Veilig uitloggen">🚪 Uitloggen</a>
             </div>
         </nav>
 
@@ -403,7 +407,7 @@ $serverSoftware = $_SERVER['SERVER_SOFTWARE'] ?? 'Apache / Nginx';
             <div style="flex: 1; min-width: 280px;">
                 <h2 style="font-size: 1.3rem; color: var(--text-main); margin-bottom: 6px;">⚡ Volledige Server Benchmark</h2>
                 <p style="font-size: 0.88rem; color: var(--text-muted); margin-bottom: 18px;">
-                    Voert in één geautomatiseerde cyclus alle 5 hardware- &amp; softwaretests uit op www.webenpcstudio.nl.
+                    Voert in één geautomatiseerde cyclus alle 5 hardware- &amp; softwaretests uit op <strong>server.webenpcstudio.nl</strong>.
                 </p>
                 <div style="display: flex; gap: 8px; align-items: center; flex-wrap: wrap;">
                     <button class="btn btn-primary" id="btn-run-all" onclick="runFullBenchmark()">
@@ -900,7 +904,7 @@ $serverSoftware = $_SERVER['SERVER_SOFTWARE'] ?? 'Apache / Nginx';
 
         function copyReport() {
             let report = "=== WEB & PC STUDIO - WEBSERVER BENCHMARK RAPPORT ===\n" +
-                `Domein: www.webenpcstudio.nl\n` +
+                `Domein: server.webenpcstudio.nl\n` +
                 `Datum: ${new Date().toLocaleString('nl-NL')}\n\n`;
 
             if (lastReport) {