Explicitly add option to edit queued policy information

we should wait for the validation email to be received & acted on before overwriting the current `domain` entry.

Start by tracing how queued policy information is stored, edited, and replaced, then find the validation-email flow that currently overwrites the `domain` entry. The work is done when an explicit edit option preserves the current entry until the validation email has been received and acted on, with the relevant behavior covered by tests.

Written by the indexing model from the issue text.