ACME DNS-PERSIST-01 builder

[ptman]

Is your feature request related to a problem? Please describe.
https://letsencrypt.org/2026/02/18/dns-persist-01

Describe the solution you'd like

PERSIST_BUILDER({
label: '@',
issuer: 'letsencrypt.org',
accounturi: 'https://acme-v02.api.letsencrypt.org/acme/acct/1234567890',
persistUntil: 1767225600, // a nicer format would be welcome as well, e.g. '2026-06-30T18:00:00Z'
})

Describe alternatives you've considered
TXT record

Additional context

Timeline is 2026Q2