An engineer, the daughter of the Austrian Jewish upper middle class, the most beautiful star of the 1930s and 1940s, an agent for the US during the Second World War and, through her patents, one of the pioneers of Wi-Fi technology, Hedy Lamarr lives on in a collection of accessories. “She didn’t care a jot about fame. She sold all her dresses,” says her granddaughter Wendy Colton