v2.6.0: Content backup/git versioning, plugin type system, docs update

New features:
- ContentBackup class with ZIP backup/restore and git versioning
- Admin backup & restore page (content-backup.twig) with git init/commit/log/restore
- Plugin type system: system (blue) vs content (green) with visual badges
- PluginAPIInterface + AdminPluginAPI for plugin architecture
- Essential plugin flag (cannot edit/deactivate/delete)

Improvements:
- Consolidated enabled_plugins config (removed plugins.enabled)
- Removed Analytics/Logging toggles from admin config page
- Fixed Dashboard plugin Twig comments rendered as text
- Updated 20 guide files (NL+EN): configuratie, plugins, plugin-development,
  core-classes, theme-json, layouts, scss-styling, admin-beheerder, nieuw-thema, architectuur
- Improved accessibility test script (grep -E, min/max checks)

Cleanup:
- Removed unused classes: ARIAComponents, AccessibilityManager, ContentSecurityPolicy, etc.
- Removed vendor packages: mustache/mustache, php-mqtt/client
- Removed old templates: logs.twig, statistics.twig (now plugins)
- Moved language files to language/ directory

Tests:
- Pentest: 30/30 passed, 0 vulnerabilities
- WCAG 2.1 AA: 25/25 passed, 100% compliance

plugins/Logs/Logs.php

@@ -0,0 +1,101 @@
+<?php
+
+class Logs
+{
+    private ?PluginAPIInterface $api = null;
+
+    public function setAPI(PluginAPIInterface $api): void
+    {
+        $this->api = $api;
+    }
+
+    public function getConfig(): array
+    {
+        return [
+            'title' => 'Logs',
+            'viewable' => false,
+            'type' => 'system',
+        ];
+    }
+
+    public function getAdminMenu(): array
+    {
+        return [
+            [
+                'plugin' => 'Logs',
+                'route' => 'logs',
+                'label' => 'Logs',
+                'icon' => 'bi-journal-text',
+                'section' => 'general',
+            ],
+        ];
+    }
+
+    public function handleAdminRoute(string $action): ?string
+    {
+        $tab = $_GET['tab'] ?? 'admin';
+        $logDir = dirname(__DIR__, 2) . '/admin/storage/logs';
+        $logFile = $tab === 'requests' ? $logDir . '/requests.log' : $logDir . '/admin.log';
+
+        $logs = [];
+        if (file_exists($logFile)) {
+            $lines = file($logFile) ?: [];
+            $lines = array_slice($lines, -100);
+            foreach ($lines as $line) {
+                if (preg_match('/^\[([^\]]+)\] \[([^\]]+)\] \[([^\]]+)\] (.+)$/', trim($line), $m)) {
+                    $logs[] = [
+                        'time' => $m[1],
+                        'level' => strtolower($m[2]),
+                        'ip' => $m[3],
+                        'message' => $m[4],
+                    ];
+                }
+            }
+            $logs = array_reverse($logs);
+        }
+
+        ob_start();
+        ?>
+        <h2 class="mb-4"><i class="bi bi-journal-text"></i> Logs</h2>
+
+        <ul class="nav nav-tabs mb-3">
+            <li class="nav-item">
+                <a class="nav-link <?= $tab === 'admin' ? 'active' : '' ?>" href="/admin/logs?tab=admin">Admin</a>
+            </li>
+            <li class="nav-item">
+                <a class="nav-link <?= $tab === 'requests' ? 'active' : '' ?>" href="/admin/logs?tab=requests">Requests</a>
+            </li>
+        </ul>
+
+        <div class="card shadow-sm">
+            <div class="card-body p-0">
+                <table class="table table-hover mb-0">
+                    <thead>
+                        <tr>
+                            <th>Tijd</th>
+                            <th>Level</th>
+                            <th>IP</th>
+                            <th>Bericht</th>
+                        </tr>
+                    </thead>
+                    <tbody>
+                        <?php if (empty($logs)): ?>
+                        <tr><td colspan="4" class="text-muted text-center py-4">Geen logs gevonden.</td></tr>
+                        <?php else: ?>
+                            <?php foreach ($logs as $log): ?>
+                            <tr>
+                                <td class="text-muted small"><?= htmlspecialchars($log['time']) ?></td>
+                                <td><span class="badge bg-<?= $log['level'] === 'warning' ? 'warning text-dark' : ($log['level'] === 'error' ? 'danger' : 'info') ?>"><?= htmlspecialchars($log['level']) ?></span></td>
+                                <td><code class="text-muted"><?= htmlspecialchars($log['ip']) ?></code></td>
+                                <td><?= htmlspecialchars($log['message']) ?></td>
+                            </tr>
+                            <?php endforeach; ?>
+                        <?php endif; ?>
+                    </tbody>
+                </table>
+            </div>
+        </div>
+        <?php
+        return ob_get_clean();
+    }
+}

plugins/Logs/plugin.json

@@ -0,0 +1,9 @@
+{
+    "name": "Logs",
+    "version": "1.0.0",
+    "author": "CodePress",
+    "description": "Toont admin activiteitlogs en front-end request logs met filter tabs.",
+    "type": "system",
+    "essential": false,
+    "hasConfig": true
+}