Federal gun policy is shifting quickly, and much of it is happening through courts and executive agencies rather than Congress. In just the last few weeks, an appeals court struck down a decades-old handgun rule, the Justice Department took positions that break with long-standing enforcement, and a rights restoration program that sat dormant for more than 30 years reopened. Here are five developments that may change the rules for gun owners, buyers, and dealers, along with what is settled and w …