1) How can I find out how many articles I have read on chess.com (other than the "award" for reading articles)?
2) How can I find out which articles I have read, so I don't have to read an article a second time?
3) What constitutes "reading" an article?
4) Is there a limit to how many articles I can read per day?
I don't think that such a list exists.
Going forward, however, you can make a comment in the articles you do read that you like. That will help you to recall if you have seen them before.
I presume nobody is making you play chess. Your question about what counts as reading makes me think that is a possibility. I think that if you only skim the first few paragraphs, and you learn nothing, it doesn't really count. Reading an article a second time is a good indication that you found it to be of value.(Can you recall any that you have read more than once?)
There is no point in just checking off articles unless you actually might have learned something.
I don't think there are limits on the number of articles you can read.
1) How can I find out how many articles I have read on chess.com (other than the "award" for reading articles)?
2) How can I find out which articles I have read, so I don't have to read an article a second time?
3) What constitutes "reading" an article?
4) Is there a limit to how many articles I can read per day?