I'm happy to say I think this baby is going to make it.
I made some peat tea by soaking a couple of cups of peat in a gallon of water overnight. Then added a small amount of Miracle Grow to it. I gave the seedling a couple of good drinks over a 24 hour period. When I checked on it just a few minutes ago here's what I found.
You can see how the veins in the leaves greened up first followed by the rest of the leaf. I'm pretty stoked about this.
Here's the before picture again for easy comparison.
Thanks to all of you with your comments and suggestions. You people and this place rock!
I've seen mosaic virus in peppers and tomatoes before, and the pattern of chlorosis is more mottles, plus there is usually some leaf distortion. When it's even like this, I usually look for nutritional deficiencies.