Does using a miniscule amount of anti-seize on a spark plug jeopardize the torque readings?
I don’t even know if you are able to calculate that.
Any lubrication will affect torque readings. Many modern plugs do not need any anti-seize due to coatings on the threaded bodies.
These days, all spark plugs have nickel plated threads, so there is no need for anti-seize on the threads.
Beyond that, I have been screwing in spark plugs for 55 years and I have never used a torque wrench on a spark plug. You can feel when the crush washer crushes, or when you hit bottom on a bevel type plug.
I put grease on my wheel lug bolts so they won’t rust and I subtract about 5 ft lbs to compensate.