By LEE KEATH, Associated Press CAIRO (AP) — The doors of jihad opened for Ayman al-Zawahri as a young doctor in a Cairo clinic, when a visitor arrived with a tempting offer: a chance to treat Islamic fighters battling Soviet forces in Afghanistan. With that offer in 1980, al-Zawahri embarked on a life that over three decades took him to the top of the most feared terrorist group in the world, al-Qaida,