DNS change tickets now persisted in MariaDB via DnsTicket model.
Survives cache clears and container rebuilds. Model has open(),
confirm(), fail() methods and pending/queued scopes. Controller
updateRecords and ticket endpoints refactored. RetryDnsTickets
command queries model instead of cache.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>