feat: P6 operacni viditelnost - audit log prohlizec, cleanup script

- audit-log.php: API endpoint s filtrovanim (akce, entita, datum, hledani) a stranovanim
- AuditLog.jsx: stranka s tabulkou, filtry, pagination, skeleton loading
- Sidebar: polozka "Audit log" pod Systemem (settings.audit permission)
- cleanup.php: CLI script - maze rate limit soubory >24h a audit log >90 dni
- Migrace: settings.audit permission

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

api/cleanup.php

@@ -0,0 +1,58 @@
+<?php
+
+/**
+ * Cleanup CLI script - maze stare rate limit soubory a audit log zaznamy.
+ *
+ * Pouziti: php api/cleanup.php
+ * Doporuceny cron: 0 3 * * * php /path/to/api/cleanup.php
+ */
+
+declare(strict_types=1);
+
+if (php_sapi_name() !== 'cli') {
+    http_response_code(403);
+    echo 'Pouze CLI';
+    exit(1);
+}
+
+require_once __DIR__ . '/config.php';
+
+$rateLimitDir = __DIR__ . '/rate_limits';
+$rateLimitMaxAge = 24 * 60 * 60; // 24 hodin
+$auditLogMaxDays = 90;
+
+$deleted = 0;
+$errors = 0;
+
+// Rate limit soubory starsi 24h
+if (is_dir($rateLimitDir)) {
+    $now = time();
+    $files = glob($rateLimitDir . '/*.json');
+    if ($files !== false) {
+        foreach ($files as $file) {
+            $age = $now - filemtime($file);
+            if ($age > $rateLimitMaxAge) {
+                if (unlink($file)) {
+                    $deleted++;
+                } else {
+                    $errors++;
+                }
+            }
+        }
+    }
+}
+
+echo "Rate limits: smazano {$deleted} souboru" . ($errors > 0 ? " ({$errors} chyb)" : '') . "\n";
+
+// Audit log zaznamy starsi 90 dni
+try {
+    $pdo = db();
+    $stmt = $pdo->prepare(
+        'DELETE FROM audit_logs WHERE created_at < DATE_SUB(NOW(), INTERVAL ? DAY)'
+    );
+    $stmt->execute([$auditLogMaxDays]);
+    $auditDeleted = $stmt->rowCount();
+    echo "Audit log: smazano {$auditDeleted} zaznamu starsich {$auditLogMaxDays} dni\n";
+} catch (PDOException $e) {
+    echo "Audit log: chyba - {$e->getMessage()}\n";
+}