Consider sqlite with sqlcipher backend

[tmpfs]

https://www.zetetic.net/sqlcipher/design/

This is what Signal uses interestingly.

[tmpfs]

There is an issue with this that the browser extension helper needs to listen for changes to the data source and there is a bug using notify with sqlite databases on MacOS that would prevent us from keeping the browser extension UI in sync as changes are made in the app, see notify-rs/notify#613.

[tmpfs]

The alternative approach to detect changes would be to avoid notify and use the hooks feature of rusqlite:

    conn.update_hook(Some(
        move |action: Action, db: &str, table: &str, id: i64| {
            println!("Update hook: {:#?} {} {} {}", action, db, table, id);
        },
    ));