BAGHDAD — The wires protruding from the small, misshapen stuffed animal revealed the deadly booby-trap tucked inside. For the people of Mosul, the sophisticated bomb was a reminder of how difficult it will be to return to homes littered with hidden explosives by Islamic State militants and dotted with the remnants of undetonated bombs dropped by the U.S.-led coalition that still could blow up. Washington at least is trying to ease a bit of the massive clean-up burden. On Thursday, the top U.S.