Add DNS monitoring and refresh functionality

Introduce DNS monitoring: add DnsService (comprehensive DNS lookup, crt.sh discovery, Cloudflare detection, IP enrichment) and a new DnsRecord model to persist snapshots, manage diffs, and provide queries/stats. Update DomainController to support a dns_monitoring_enabled flag, refactor WHOIS/DNS refresh logic into performWhoisRefresh/performDnsRefresh, and add endpoints for refreshWhois, refreshDns and refreshAll; send notifications when DNS monitoring is toggled. Add UI templates/tabs for DNS, billing, notifications, overview, SSL and WHOIS and wire DNS data into the domain view; expose cached IP details. Add cron/check_dns.php and migration 027_add_dns_monitoring.sql (and include it in installer migration lists). Other tweaks: safer EmailHelper subject handling, TldRegistry search improvements, domain sorting using an effective status (expiring_soon), Discord channel null-safe fields, settings UI additions (domain_view_template and cron staleness warnings), and route/migration updates. This enables scheduled and manual DNS scans with persistent records and notifications.

app/Views/domains/index.twig

@@ -369,7 +369,7 @@
                                     <a href="/domains/{{ domain.id }}" class="text-blue-600 hover:text-blue-800 dark:text-blue-400 dark:hover:text-blue-300" title="View">
                                         <i class="fas fa-eye"></i>
                                     </a>
-                                    <form method="POST" action="/domains/{{ domain.id }}/refresh" class="inline">
+                                    <form method="POST" action="/domains/{{ domain.id }}/refresh-whois" class="inline">
                                         {{ csrf_field() }}
                                         <button type="submit" class="text-green-600 hover:text-green-800 dark:text-green-400 dark:hover:text-green-300" title="Refresh WHOIS">
                                             <i class="fas fa-sync-alt"></i>