The Lincoln-Sudbury Regional School Committee announced Tuesday that it had voted unanimously to extend the contract of Bella Wong as the district’s interim superintendent and principal through the 2014-2015 academic year. Officials said the decision was made to provide continuity at a time when administrators in the high school are new to their roles. Several new initiatives are also being implemented, including a statewide educator evaluation. “We are pleased to have extended Bella’s contract for an additional year in order to provide stable leadership at an important time,” said Radha Gargeya, the school board’s chairman. Wong was hired in July to serve as the district’s interim leader. She previously served as superintendent of the Wellesley school system for five years, after six years as the district’s assistant superintendent. The School Committee plans to reevaluate its strategy for hiring a permanent superintendent/principal next spring, with input from the community.