SourceQuery gains `front` (serde default false, so an old client's request
decodes as before). The one owner of the list is sources::FRONT_PAGE_FILES;
the Qdrant filter matches `path` against it with MatchAny on the existing
keyword index, composed with the `repo` condition. The CLI prints the
citation line range as before.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>