Last week, a new Broadway musical, “Maybe Happy Ending,” opened to rave reviews. It’s an eccentric, endearing story, set in 2064, about two retired robots who fall in love. One of its authors, Hue Park, is Korean and the musical is set in both Seoul and an island off the Korean peninsula. The show was originally a hit in South Korea, playing in Seoul in 2016, with five subsequent productions. Jeff Lunden in New York gives us a peek into the production.