The sale of the nation's largest federallysubsidized housing project in Brooklyn will go forward after itsowners agreed to ensure that it would be preserved as affordablehousing. The owners of Starrett City reached the agreement with federal,state and city officials, allowing the sale of the development tobegin this week. The 140-acre complex was slated to be sold for $1.3 billion lastyear, but the deal was blocked out of concerns that the high pricewould lead the new owner to raise rents on the more than 5,000apartments. Tenants and housing advocates have embraced the accord thatwould keep the housing project affordable for its mostly workingand middle-class residents.