Bichon can run on a laptop, and restarts or reboots are not a problem — you just need to make sure it starts automatically when the system boots. It is a standalone executable that is configured via command-line arguments or environment variables.

I’ve also been considering packaging it as a desktop application so that non-technical users can use it more easily, since there are Rust projects that can help wrap Bichon into a desktop app.

What I would like is an app that I can let loose on my Maildir directory and indexes and allows search. It doesn't need to receive mails or download (or send) them.