Original poster here with a belated conclusion. I was finally able to drive the car today after dealing with an extended and unrelated starting issue. I appreciate all the suggestions on the rack/pump/belt. The winner, so far, is the advice to bleed the system and add a bottle of stop leak. I did this and ended up adding probably 1/3 bottle of Lucas Stop Leak in the process. Drove the car for about 12 miles and no more unusual noise from under the hood. I’ll monitor the PS fluid level and see if things hold up. It certainly beats replacing the pump and/or the rack. Thanks folks.