It’s an exhilarating thought: a musical tribute to Harlem staged at its famous Apollo Theater, written and directed by George C. Wolfe, who’s been responsible for so many revelatory shows about black culture and tradition (most notably, Bring in ‘Da Noise, Bring in ‘Da Funk). But while, in concept, Harlem Song is an event, it’s too cursory to be a full-bodied celebration. The problem: It’s conceived less as a play than as an educational project — an infomercial for the neighborhood’s riches, complete with newsreel footage, photos, and filmed ”witnesses” to Harlem history. Wolfe and his strutting, sleekly costumed cast raise the roof as they speed from blues to jazz to funk. But while it works as a gloss, too much of this bright production succumbs to cultural and theatrical cliche.