Review found two Memory-only tests behind a README claim that every integration test runs
twice. Both are now generated by both_transports!: the one-agent composition, and the
old-epoch refusal, which is one of the three tests the old-worker-replies row cites. The
README says which single test walks both transports inside itself instead, because it
compares their traces against each other.
step-v1 section 2 gains the mid-step pause line and a dated amendment saying why it is not
a new edge: a pause requested during a transition is the ordinary
Committing(k) -> Ready(k+1) edge followed by Ready(k+1) -> Paused(k+1), because section 6
requires the transition to finish first, so the only boundary such a pause can land on is
the one the transition just committed.
