LAURIE GOERING FROM spray parks in water-short Cape Town to heat-reflecting pavements in Tokyo, cities around the world that face worsening heatwaves as the planet warms are rapidly adopting innovations to try to beat increasingly deadly heat. But ensuring the measures help those most at risk remains a challenge, for reasons ranging from racial discrimination to funding and policy deficits, as well as misperceptions about who is most vulnerable and where, heat experts said this week. In New York, for instance, most deaths from heat stress occur at home, Kizzy Charles-Guzman, deputy director of the city mayor's resiliency office, told…