Thanks for the warm welcome. I think you might be right about the repeat puncture. It was my first tire change and I didn't think to shake out the tire before putting a new tube in. Naive mistake. Live and learn.

My friend couldn't take me to the bike shop at lunch today. Luckily, I had a patch kit in my seat bag so I repaired the repeat-punctured tube.

The valve wasn't broken on the replacement tube like I thought. I just got a little overzealous with the hand pump.

It's a little tough to see, but the rubber separated where the stem connects.