Accept boolean transfer-lock values from Hover domain list

Live gocodealone-dns reconciliation hit a Hover /api/domains decode failure during delegation preflight:

json: cannot unmarshal bool into Go struct field Domain.domains.locked of type string

Hover has returned string values like "on", but the live response now includes boolean locked values for at least one domain. The client should accept both shapes so domain enumeration and transfer-lock reads remain compatible.