my questions is what is the maximum daily post limit for a web site that google never flagged there is spam.
I think their is no such limit. But you can try to be a little more conscious on whatever you are posting. Since, it should not look spam or it should not be fake that can be flagged as spam.
No limit, always trying to keep relevancy, intact with your theme concern, never go beyond the Google guideline......as usual you can explore more....
No such rule for that but always keep in mind that make the post as Spam, try to make that simple and relevant, make that post as quality post because google look for the quality but not for the quantity, don't try to cross google guidelines. That's it.
I think there is no limit on posting posts but posts always should be quality and never post spammy content.
There is no limit on posting but the content of your posts has to be really good. Also, try not to repeat your content, Google notices that.