NARVA, Estonia — Right on the Russian border, Europe’s first commercial-scale rare-earth magnet factory is starting to supply automotive and green tech customers from a forgotten corner of Estonia. The project represents an act of defiance against Russian aggression. It’s a bid to counter China’s chokehold over critical minerals that is Beijing’s trump card in its escalating trade war with the United States. And it’s a vote of optimism regarding European industry, its backers say. “The future