OpenAI is reinstating CEO Sam Altman to its board of directors and said it has “full confidence” in his leadership after an outside investigation into the turmoil that led the company to abruptly fire and rehire him in November.OpenAI said the investigation by the law firm WilmerHale concluded that Altman’s ouster was a “consequence of a breakdown in the relationship and loss of trust” between Altman and the prior board.The ChatGPT maker also said it has added three women to its…