SAN FRANCISCO – The plot to oust Uber chief executive Travis Kalanick began almost the moment he announced June 13 that he was taking a temporary break from the celebrated technology company caught up in scandals. The audacious effort to end Kalanick’s run atop one of Silicon Valley’s most successful start-ups was led by one of the company’s own board members, Bill Gurley, a major investor, according to two people familiar with the board’s thinking. Even as Uber’s board of directors publicly appeared to support him, Gurley, a venture capitalist and early Kalanick backer, rounded up other Uber investors who also said that Kalanick simply could not return to the ride-hailing company he co-founded and grew from small start-up to a company worth an estimated $69 billion, according to the people, who spoke on the condition of anonymity because of the confidential nature of the discussions.