I know exactly what you mean, having seen that done in ebooks I've purchased.
We do allow authors to add a Table of Contents to oneshot or drabble collections, but in terms of a novel-length chaptered fiction, we've not allowed a table of contents chapter.However, the archive code as it currently stands doesn't allow for links within chapters. It would be a list of URLs that the reader would need to copy and paste anyway.
What we do have, for now, is the dropdown of the chapters, which lists each chapter by number, and by name if the author has named them. You can then scroll the dropdown to the chapter you want to read. It's just as quick, and that is the goal, I think.