Thousands March to Holy Shrine in Najaf NAJAF, Iraq - Radical Shiite cleric Muqtada al-Sadr ordered his fighters to lay down their arms and leave the area as thousands of Iraqis thronged the revered Imam Ali shrine Friday after he and the Iraqi government agreed to a peace proposal by Iraq's top Shiite cleric to end three weeks of fighting in Najaf.    Al-Sadr issued the order in a statement to his Mahdi Army militia from his office in Najaf that also was broadcast through loudspeakers at the shrine, which militants have used as a stronghold and refuge throughout their standoff with a combined U.S.-Iraqi force...