When fires devastated luxury homes in Fairfield and Westchester counties, a Chubb Corp. insurance adjuster was there to assess damages and start the restoration process.But Chubb did not know that its own adjuster was colluding with a contractor he hired to estimate repair costs. The contractor inflated the estimates and the adjuster steered the repair work back to the contractor. A federal jury in White Plains recently ruled unanimously, in a 40-day trial, that the adjuster, Dennis Sorge, and the contractor, Paul H. Mertz Jr. and the Mertz Co., are liable for fraud and breach of fiduciary duty.