It certainly doesn't seem like it's within our grasp on HN. Looking at the December 2021 "who is hiring" thread, I see four posts which offer "part-time" but aside from that nothing which specifies that either a 4-day or sub-40-hour workweek is an option.
Thank you, I did. :) While I'm not looking for a position at this moment, I've added Bolt to the list of companies I'll actively consider when I'm back in the market a few months from now.