Goal
Given a book_title (and optionally author), return the first/best matching https://www.livelib.ru/book/... URL from LiveLib search.
Inputs
book_title(string)
Output
book_url(string | null)candidates(list)
Notes
- Use as fallback when the reading list search fails.
- If no book is found, return
book_url = null.
See references in references/.