Purdue Pharma, which helped revolutionize the prescription painkiller business with its drug OxyContin, is proposing a $10 billion plan to emerge from bankruptcy that calls for it to be transformed into a different kind of company funneling profits into the fight against the nation’s intractable opioid crisis.Those efforts would include a significant boost — more than $4 billion — from members of the Sackler family who own the Connecticut-based pharmaceutical giant.The plan, filed late Monday night in U.S Bankruptcy Court …