The doors opened early on Causeway Street on April 11, and by the time the puck dropped, 17,850 fans had devoted their Saturday nights to filling the stands for a historic moment. For the first time, the Boston Fleet took the ice at TD Garden, hosting the Montréal Victoire in front of a sold-out crowd that felt equal parts celebration and statement. Women’s hockey had arrived on one of the sport’s biggest stages, and the crowd was ready for it.