ASBURY PARK, N.J. — I’m riding down Kingsley, looking for a place to park. With the crowds at Convention Hall, the Stone Pony and the Wonder Bar, there are no spots left on this oceanfront stretch. I’m here to see the roller-derby championship, three weeks after Hurricane Sandy ripped through and devoured the boardwalk. It’s night, and a waxing moon barely lights the culprit — the churning Atlantic, which both gives this place its life and threatens its existence.