A document with no preview yet answers 404 when the screen asks for its current
one, and the screen turns that into "make a preview". The sweep counted it as a
failure, so every run ended with the same red line under a healthy deployment.
A check that cries wolf on every run stops being read, and a real failure would
have sat unnoticed beside it. The session probe's 401 before sign-in is the
same kind of expected answer and is excluded on the same terms; every other
4xx and 5xx still fails the sweep.
DongHyeonka
7289ce97bb