Travis Kalanick’s drive to win in life has led to a pattern of risk-taking that has at times put his ride-hailing company on the brink of implosion. SAN FRANCISCO — Travis Kalanick, the chief executive of Uber, visited Apple’s headquarters in early 2015 to meet with Timothy D. Cook, who runs the iPhone maker. It was a session that Mr. Kalanick was dreading. For months, Mr. Kalanick had pulled a fast one on Apple by directing his employees to help camouflage the ride-hailing app from Apple’s engineers. The reason?