The Post’s David Nakamura reports that Mayor Adrian Fenty plans to endorse Barack Obama for the Democratic presidential nomination. An official announcement has yet to come, but the actions of Fenty adviser Jim Hudson, who organized a fundraiser for Obama, suggest the mayor looks set to get behind the Illinois senator’s campaign. Hudson collected $600,000 and endorsements from some of the mayor’s more loyal D.C. Council members: Yvette Alexander (D-Ward 7), Muriel Bowser (D-Ward 4)…