Post Visibility Check

Is a post still publicly visible, or did it quietly stop being so? A removed Reddit post still returns when fetched by id, with its title, body and score, so this cannot be answered by reading the post. It is answered by fetching the post and then one page of its author's submitted listing and comparing. Returns a verdict of live, not_visible or undecidable, a plain-language reason, and a confident flag. It deliberately never names a CAUSE: a moderator removal, an admin removal, a spam filter and an author who has hidden their post history are indistinguishable from outside, and only one of them is "removed". Exactly two upstream calls. Cost: $0.004 per call.