NEW YORK, May 29 : U.S. stocks followed world shares higher and crude prices retreated on Friday as investors neared the end of a holiday-shortened week with renewed hopes of progress toward a peaceful resolution to the Iran war. A narrow, tech-led rally lifted all three major U.S. stock indexes to modest gains while benchmark U.S. Treasury yields dipped for a fourth straight session, as markets turned the page on a week and month marked by fears that a fragile truce would collapse amid signs