Add multiple security and validation improvements across the app:
- Prevent session fixation: regenerate session ID on login and after successful 2FA; tighten session cookie params (Secure, HttpOnly, SameSite=Lax).
- Harden installer: add CSRF checks for install/update flows and use PDO::quote when injecting admin credentials into SQL migration to avoid injection; add csrf_field() to installer templates.
- Template hardening: add safe_url and safe_mailto Twig filters, escape tag names for JS, and add rel="noopener noreferrer" to external links to mitigate XSS/opener risks.
- Domain controller: validate referrer to avoid open redirects, enforce user isolation mode when finding/deleting/updating domains and when assigning notification groups (ensures users only affect their own resources).
- Notification groups: verify channel belongs to group before deleting or toggling to prevent unauthorized access.
- ErrorLog: whitelist allowed sort columns to avoid arbitrary column injection in ORDER BY.
- Routes: move the debug whois route to protected/admin area.
These changes collectively reduce attack surface (XSS, open redirect, session fixation, SQL injection) and enforce proper resource isolation and input validation.
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.
