The overnight stock market has already faced one real crash. It handled it by canceling $437 million of trades and telling 90,000 investors their gains and losses never happened. The day was Monday, August 5, 2024. The Nikkei had its worst day since 1987 and sell orders flooded into Blue Ocean ATS, the venue that runs roughly 90% of US overnight volume and powers Robinhood's 24 Hour Market. At 1:45am ET the matching engine buckled. Every trade between 1:45 and 3:06am was nullified. Korean…