The Supreme Court ruled on Thursday that New York’s century-old concealed carry handgun law violates the Second Amendment, a finding long feared by local officials who viewed the law as a linchpin in efforts to curb the proliferation of pistols on New York City streets. The 6-3 decision, which is the court’s most significant gun rights ruling in more than a decade, rejected the state’s Sullivan Act, a regulation that limited concealed carry handgun licenses to New Yorkers with specific defense needs. The court’s conservative majority was widely expected to gut the gun law after hinting at thei…