Members of the San Francisco Chronicle Unit of the CA Media Workers Guild Local 39521 voted Saturday by a 10-1 margin in favor of a Hearst Corp. proposal designed to avoid sale or closure of the newspaper. Given the inevitability of approximately 150 layoffs in the coming weeks, the vote reflected the urgency by union members to approve an agreement for a generous severance package for all employees let go--the agreed-upon package includes a year of full pay and health benefits.