Enhance DNS discovery, validation & transfers

Add comprehensive DNS management and input validation, plus safer transfer and logging behavior.

- Add CronHelper utilities for cron scripts and unify logging/formatting.
- Improve InputValidator: sanitizeDomainInput and validateRootDomain (handles multi-level TLDs) and use throughout domain import/create flows to reject subdomains.
- DomainController: refactor DNS refresh to support quick/deep discovery (background deep scans), add endpoints to discover, add/delete/bulk-delete DNS records, import BIND zone files, enrich IP metadata via enrichIpDetails, and strengthen bulk import/reporting messages.
- DnsRecord model: add source column handling (discovered/manual/imported), avoid auto-deleting manual/imported records, and add helpers for deleting, bulk deleting, manual adding and importing zone records.
- Tag, NotificationGroup and Domain transfer logic: unlink groups when ownership changes, remove tags that belong to other users, add audit logging via Logger and improved bulk transfer reporting. TagController/View: show transferable users for admins and skip global tags on transfer.
- Notification channels (Discord, Mattermost, etc.) and EmailHelper: allow explicit subjects and improve payload fields based on notification type.
- Add new migration 029_add_dns_record_source.sql and wire it into the installer; update migrations detection.
- Add new views/partials for confirm/import/transfer modals, update various domain/group/tag templates, and update cron scripts and routes for discovery.

These changes preserve manual/imported DNS records, improve root-domain validation, enable background deep discovery, and add better logging/audit trails for transfers and imports.

app/Helpers/CronHelper.php

@@ -0,0 +1,90 @@
+<?php
+
+namespace App\Helpers;
+
+/**
+ * Shared utilities for cron scripts (logging, formatting, DNS checks).
+ *
+ * Replaces the standalone functions that were duplicated across
+ * check_dns.php, check_ssl.php, and check_domains.php.
+ */
+class CronHelper
+{
+    private string $logFile;
+
+    public function __construct(string $logFile)
+    {
+        $this->logFile = $logFile;
+    }
+
+    /**
+     * Write a timestamped message to the log file and echo it.
+     */
+    public function log(string $message): void
+    {
+        $timestamp = date('Y-m-d H:i:s');
+        $line = "[{$timestamp}] {$message}\n";
+        file_put_contents($this->logFile, $line, FILE_APPEND);
+        echo $line;
+    }
+
+    /**
+     * Log elapsed time since a given microtime start.
+     */
+    public function logTimeSince(float $since, string $prefix = '  ⏱ '): void
+    {
+        $this->log($prefix . self::formatDuration(microtime(true) - $since));
+    }
+
+    /**
+     * Short human-readable duration: "3.2s" or "2m 14.1s".
+     */
+    public static function formatDuration(float $seconds): string
+    {
+        if ($seconds < 60) {
+            return sprintf('%.1fs', $seconds);
+        }
+
+        $minutes = (int) floor($seconds / 60);
+        $remaining = $seconds - ($minutes * 60);
+        return $minutes . 'm ' . sprintf('%.1fs', $remaining);
+    }
+
+    /**
+     * Verbose elapsed time: "3.25 seconds", "2 minutes 14.25 seconds", etc.
+     */
+    public static function formatElapsedTime(float $seconds): string
+    {
+        if ($seconds < 60) {
+            return sprintf('%.2f seconds', $seconds);
+        }
+
+        if ($seconds < 3600) {
+            $minutes = (int) floor($seconds / 60);
+            $remaining = $seconds - ($minutes * 60);
+            return sprintf('%d minute%s %.2f seconds', $minutes, $minutes !== 1 ? 's' : '', $remaining);
+        }
+
+        $hours = (int) floor($seconds / 3600);
+        $minutes = (int) floor(($seconds - ($hours * 3600)) / 60);
+        $remaining = $seconds - ($hours * 3600) - ($minutes * 60);
+        return sprintf(
+            '%d hour%s %d minute%s %.2f seconds',
+            $hours,
+            $hours !== 1 ? 's' : '',
+            $minutes,
+            $minutes !== 1 ? 's' : '',
+            $remaining
+        );
+    }
+
+    /**
+     * Check whether a hostname resolves at all (SOA, A, or AAAA).
+     */
+    public static function hostnameResolves(string $hostname): bool
+    {
+        return @checkdnsrr($hostname, 'SOA')
+            || @checkdnsrr($hostname, 'A')
+            || @checkdnsrr($hostname, 'AAAA');
+    }
+}