Lululemon’s board members were under pressure. The company’s estranged founder had launched a proxy fight, with a big-name activist investor waiting in the wings, and the board was being pushed to quickly recruit a new chief executive who could turn things around.  When Lululemon landed on former Nike executive Heidi O’Neill for the job last week, Chairwoman Marti Morfitt and the board thought they had it in the bag. But the pick backfired spectacularly. Lululemon shares tanked, falling 13% the day of the announcement, and they have declined further since. Wall Street analysts critiqued her tenure at Nike, and investors complained that…