DNS validation - Copy buttons for the name fields in addition to the content during setup.

### What problem are you trying to solve?

Make lives easier when sitting on the couch with a laptop instead of typing in the challenge domain by hand or selecting the string to copy manually.

### Describe the solution you'd like

The A / AAAA wouldn't be bad either, but I wouldn't mind having a copy paste on the challenge CNAME's name field

### Describe alternatives you've considered

selecting with mouse, typing freehand

### Documentation, Adoption, Migration Strategy

_No response_

Start by locating the DNS validation setup UI and its challenge CNAME name field. Review how the existing content-field copy action works, then check whether the requested A/AAAA fields are part of the same flow. Done means users can copy the requested DNS name without selecting or typing it manually.

Written by the indexing model from the issue text.