The Dow Jones Industrial Average notched its first record close of the year Friday, rising more than 800 points after Federal Reserve Chair Jerome Powell opened the door for the central bank to lower interest rates in September. Investors had bet on caution from the central bank chief, but Powell’s speech instead highlighted the vulnerability of the labor market and signaled that the Fed could shift its wait-and-see approach. Stocks and bonds rallied, the dollar fell and gold rose more than 1%.