President Obama held his 12th state dinner Tuesday, this one for Prime Minister Lee Hsien Loong of Singapore, and it’s the sixth that Boston party planner Bryan Rafanelli has had a hand in arranging. (Last we heard, Rafanelli was on the list to attend the dinner, which would be a first for him.) The state dinner for the prime minister and his wife, Ho Ching, marks the 50th anniversary of bilateral relations between the United States and Singapore, an island nation of about 5.7 million people. After dinner, R&B and soul singer-songwriter Chrisette Michele was scheduled to entertain guests.