The second week of August isn’t ordinarily a time given over to novelty and ambition in New York. The air is a jellied vapor of sweat and refuse, and anybody who can afford to be elsewhere is. But the vast Queensbridge housing complex was an unlikely scene of neon-vested hustle. The six-story brown-brick apartment blocks along 41st Avenue had been encased in green scaffolding and draped with long, heavy bolts of cream burlap, which gave the blunt rectilinear forms a veil of anticipation.