You spent 14 months and $1.8 million turning a Carroll Gardens brownstone into your dream home. The GC handed you the keys in March. By August, the third-floor bathroom is leaking into the parlor ceiling, hairline cracks are spidering across the freshly plastered walls, and the "bespoke" white oak floors are cupping in six rooms. The contractor stopped returning calls two weeks ago. This is when most owners start asking about construction defect claims in New York —