Canada’s main stock index opened lower on Thursday, a day after U.S. President Donald Trump imposed a 25% tariff on auto imports, expanding a global trade war and hammering stocks globally. By 10:17 a.m. ET, the Toronto Stock Exchange’s S&P/TSX composite index was down 16.92 points, or 0.07%, at 25,144.14. In early trading, Canadian auto parts manufacturers fell with Magna International Inc. down 7.5% and peers Martinrea International Inc. and Linamar Corp. sliding 2.6% and 4.7%, respectively. Wall Street’s main indexes slipped on Thursday, as President Donald Trump’s latest tariff gambit sent auto stocks into a tailspin, while investors sifted…