Launching with $3.5 million in funding from Khosla Ventures and Shopify founder Tobias Lutke, Casca is taking a new approach to the footwear supply chain—designed from the ground up to support mass-produced, 3D-printed recyclable insoles customized to the exact specifications of each consumer’s foot. Casca’s leather-upper Avro ($198) and Avro Knit ($178) styles are available…