As a child growing up in Mountain Home, Katie Siira learned to lean on her older sister Kari, observing how effortlessly her elder sibling by just 11 months seemed to coast through life, constantly smiling and making her presence known in almost any social setting. Kari’s endless energy and unrestrained boisterousness, including as teammates in youth soccer and volleyball, allowed her much shyer, younger sister to sit back and watch as she worke…