> The key is not to use any code that won't be supported in 40 years. So that means no databases.
A database could help resolve your search problems. Postgres has been around in some form for over 40 years and has never been as popular as it has been now. It has a good shot of still being around and runnable in some form in 40 years, I think. It has full text search, and even trigrams for fuzzy search.