I'm looking for some advice on how to deal with punctuation following
cross-references, where:

- The cross-reference style should include surrounding quotes
- The cross-reference may be followed by punctuation, but the
  punctuation should be placed inside the closing quote.

In DocBook, <xref> has an xrefstyle attribute that might be
used to select quotes around the cross-reference title, but
(as far as I can see) that doesn't help with the punctuation
problem, because you'd normally write the <xref> as something
like this: <xref linkend="xxx", xrefstyle="yyy"/>.
The punctuation isn't part of the tag or its content, so it's
not evident to me how a transform might deal with this.