STOCKHOLM — Lufthansa could face “unlimited” compensation claims for the crash that killed 150 people in the French Alps, and it would be difficult, even counterproductive, for the German carrier to try to avoid liability, experts said this week. Under a treaty governing deaths and injuries aboard international flights, airlines are required to compensate relatives of victims for proven damages of up to a limit currently set at about $157,000 — regardless of what caused the crash. But higher …