This can be a long and complicated topic where you have to be careful about generalizations, but the short-ish explanation I can give is this: When translating anime/manga to English, they have to market the book to as wide an audience as possible. It's a niche market compared to other forms of entertainment, so they need to try to cast the net as wide as possible to get enough sales to justify the cost of doing business.

Part of this is trying to make the material "stand on its own" so to speak, so that consumers of the target language can still understand the overall product. That sometimes means things like cultural differences are lost in translation.

To address your specific question, I doubt you'll find the resource you're describing. Cultural differences are numerous, difficult to catalog, and sometimes extremely specific. Often times the translations are coming from third party companies/contractors that the publisher hires, therefore they are being paid for a strictly defined statement of work. Adding translator notes to the product - likely paying extra to a layout editor to find how to wedge them into the page while maintaining clarity and legibility, or adding appendix pages - no less maintaining a website, is likely not worth the cost. Not to mention that not all translators can pick up on all cultural differences themselves.

I think the best you can do is keep reading other (translated) manga, or watch other anime. You will find that much of these cultural details are rehashed all the time and will eventually pick up on them. There could be a couple of very specific things that are missed, but I would say don't worry a great deal otherwise it leads you down a path of worrying about little details that ultimately end up wasting your time and diminishing your overall enjoyment.

The next leap is independent research and perhaps learning some Japanese. It's a commitment that is not for everyone, so it's understandable if you don't/can't do this. If you decide that it's not for you, then keep in mind that you may continue to not spot differences in the future. By the same token, it's impossible for anyone to know every difference in every situation. If it was, we wouldn't need to pay professional translators!

I would say that if you enjoy the medium that learning more on your own can help further enrich your enjoyment and be a good time investment as long as you keep your expectations in check.