Update: A year after getting the car, our local service center was finally able to get replacement left and right front struts for an April 7 appointment, and they were replaced. Clunking diminished from about 100 clunks on the mile of road between home and the highway to maybe 10-15 clunks, but has not gone away. The car had begun to develop a little "looseness" and rattling and "stepping" over expansion joints and railway crossings. This is now resolved and the car feels tight again, but there is still that low-speed clunking which I have never experienced in any other car that didn't have serious wear issues (been driving for over 50 years).
Interestingly, the loaner I got had a VIN only four numbers higher than that of my vehicle, in the 321xxx range. It also had the clunking problem, similar to my car before the fix, but without the "looseness". The loaner also made small cracking noises when turning tightly at low speeds, especially parking, something to look forward to with mine, I guess. The loaner had 11,000 miles on it. This helps me understand why Tesla service people think the noise is "normal".
The two stabilizer links had been previously been changed during a mobile service visit with no improvement in the clunking. My invoice does not specify that an alignment was done, even though a service tech said that the strut change needed to be done at the service center BECAUSE an alignment was necessary after changing the struts. I will look into it.
From my reading here that leaves the steering rack and the upper control arms as possible culprits. Have to see if Tesla can get both those done during year 2 of ownership. Hopefully I'll get it fixed before the warranty is up! Tesla is certainly not very proactive on this issue.