Before going to a street takeover in Belltown on Sept. 6, 17-year-old Kaleb Osborne promised his worrying mother, “I’ll be home and I will not get shot.” Amanda Osborne, his 38-year-old mother, had set rules for the teenager after the takeovers he attended had turned dangerous: Don't get too far into the crowd and don't start anything with anyone, not even to help his friends. But now, she is grieving the loss of her oldest son after he was kill…