<p>Jack Antonoff, the producer, finally got a night off on Friday. As his band Bleachers kicked off a new tour at Salt Shed, for once the focus turned away from the nonstop work he’s done for other artists to his main gig: the indie pop project he founded in 2013, before he was building up his cache of pop star cohorts.</p><p>OK, yes, Antonoff did just drop the new Taylor Swift “Toy Story 5” song, “I Knew It, I Knew You,” the same day and managed to slip in an acoustic cover of Lana Del Rey’s “Margaret” into the set. But still, the heart of this 105-minute concert<b> </b>was Antonoff’s strong acumen as a songwriter and the unbridled joy he always brings to the art of making music.</p><p>The night’s draw was promoting Bleachers’ latest album, “Everyone for 10 Minutes” (also the name of an AirDrop setting for file sharing on mobile devices, which only a producer like him would think of).