Optimism about the economy swept through the market Friday, pushing two key indexes past major milestones. After weeks of mixed signals about manufacturing and earnings, a surprisingly strong US jobs report gave investors confidence that the economy isn’t about to falter. The market jumped from the opening bell. Traders donned party hats, and a wave of buying helped the S&P 500 index crack the 1,600 mark for the first time. The Dow broke through 15,000. Jobs are crucial to keeping the stock market climbing. The S&P 500 is up 13 percent from the start of the year. The Dow is up 14 percent.