The Mets sent Carlos Beltran to the Giants in July, but they were surprisingly unwilling to deal any of their lesser free-agents-to-be, a group that included Chris Capuano, Scott Hairston, Willie Harris, Jason Isringhausen and Tim Byrdak.  Today they retained the least expensive member of that bunch for 2012, signing the 37-year-old Byrdak to a one-year extension.…