Tenzin Gyatso has said on multiple occasions that he may be the “last” Dalai Lama. But as thousands of Tibetan Buddhists gather in the northern Indian town of Dharamsala to celebrate his 90th birthday on July 6, spilling out of temples into nearby parking lots and courtyards in the Himalayan foothills, the spiritual leader of a religion whose future has been mired in uncertainty offered a more affirming message. “The institution of the Dalai Lama will continue,” the 14th Dalai Lama said in a