A person navigates the Temu website on a smartphone in Toronto, on April 4.Giordano Ciampini/The Canadian Press It started with a video of a postal worker sorting a mountain of orange packages from Temu. Rachael D’Amore hadn’t heard of the online shopping site, but after watching the video she found good reviews, affordable products and free shipping on most orders – what she called “a unicorn in Canada these days.” “I had to double check the URL to make sure that I wasn’t on the U.S. site,” she said. Temu also offered a $5 credit if an order took longer...