Are my home canned tomatoes safe?

Just another comment agreeing with Lori T and aargersi. OK to eat with the black seeds unless you see sign(s) of spoilage.
With support from Penn State Extension service.
https://extension.psu.edu/canning-and-freezing-questions-and-answers#:~:text=this%20from%20happening.-,Question%3A%20Black%20seeds%20in%20home%20canned%20tomatoes%2C%20is%20there%20any,tight%20seal%2C%20has%20been%20maintained.

So long as you followed all the proper procedures for canning them, then the most likely explanation for the seed color is a chemical reaction between seeds, water and juices. Hard water, in particular iron content, will do this. You will also find black or dark brown seeds inside a fresh tomato as well- that's generally a dead seed, in an overripe tomato. As the tomato gets older, well - the seeds inside do as well, and some just don't make it. There is a chemical explanation there as well, but it's long and boring. Anyway, so long as you don't see other signs of spoilage, and you broke an intact seal to get to those tomatos, they will be fine.

Did you have enough acid when you canned them (added lemon) and was the seal intact? It can be iron in the tap water that causes the seeds to turn black, if they look and smell ok, and the seal was tight, I think you’re fine.
That said, if there’s ANY indication that theyve turned … bubbles fizzing of course MOLD … toss them. Not worth the risk.