It looks awfully close to me. I suppose you could go on a very slow, easy ride and if it rubs when you hit a bump switch it out. Hopefully if it rubs it won't lock up though....

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Madison photographer Timothy Hughes | Instagram

In a Cylingtips article they mention 4mm clearance being the minimum according to ISO standards.

"There was ample clearance for the 28c tyres on both bikes, however this is the largest tyre size that Cannondale can recommend without contravening strict ISO standards (that dictate a minimum of 4mm clearance)."

https://cyclingtips.com/...e-comparison-review/

I would think that should be okay. I suspect lots of people have the centre of rim brake calipers that close to their tyre. I don't think you get much radial movement on a wheel, or tyre at the top unless there's a major failure, in which case no clearance is necessarily safe. I'd probably feel happier with a bigger gap but objectively I doubt it's actually a big risk.
Lateral clearance, especially at the back wheel is likely more of an issue due to lateral flex under load.

I probably should have noted that I'm 144 lbs so deformation of the wheel or time is probably unlikely.

Looks fine to me. I'd go ride it into a tailwind (you can hear your bike better in a tailwind) and do a few out of saddle sprints. If you don't hear it rub, it should be fine. Even if you do hear it rub a bit, it's still probably fine.

If you break a spoke on race day, you may be in trouble. Otherwise, you should be good.