This tall, black, shaven-headed character actor of TV and film projects both poignancy and mischievous intelligence with ease. Michael Boatman is best recalled as Private Samuel Beckett, the soldier who ran the morgue, in the critically-acclaimed ABC series "China Beach" (1988-1991), and, more recently, as Carter, the gay mayoral advisor, on "Spin City" (ABC, 1996- ). The actor's career received a boost when he performed at the Kennedy Center in Washington, DC, and won a Best Supporting Actor award in the prestigious Irene Ryan National Competition while still an undergraduate. Boatman also