The diagnosis so far, what has been ruled out, and the three read-only checks that would confirm or refute it — with slots to paste the output into and a note against each saying what the answer means.
Written as a working document rather than a summary because the decisive check has a timing constraint that is easy to miss: the Postgres service container is deleted when the job finishes, so watching it has to happen during the run. Discovering that after the fact costs another full run.
It also records the negative result deliberately. If the container is healthy throughout, the hypothesis is wrong and the document says which suspect is next, rather than leaving an abandoned theory for the next reader to re-derive.
Refs #154
