Mortgage rates are still drifting higher for their fourth straight week, and fresh inflation data suggests home buyers may not see much relief anytime soon. The average rate on a 30-year fixed-rate mortgage rose four basis points to 6.46% APR in the week ending May 28, according to rates provided to NerdWallet by Zillow. (A basis point is one one-hundredth of a percentage point.) We calculate our weekly average using daily APRs recorded over the past five business days. All things considered, four basis points is a relatively modest increase given the ongoing instability in the Middle East. This week brought a mix of headlines, from new U.S. strikes on Iranian targets to a possible peace framework that could reopen the Strait of Hormuz, a key route for global oil shipments. Since the war in Iran began, bond markets have been rattled by every twist in the conflict. Today’s mortgage rates tend to follow bond yields, so they’ve been jumpy, too.…