WASHINGTON — The agreement by the maker of OxyContin to settle thousands of lawsuits over the harm done by opioids could help combat the overdose epidemic that the painkiller helped spark. But that does not mean all the victims are satisfied.In exchange for giving up ownership of drug manufacturer Purdue Pharma and for contributing up to $6 billion to fight the crisis, members of the wealthy Sackler family would be exempt from any civil lawsuits. At the same time, they could potentially keep billions of dollars from …