The `Dry-run publish validation` step ran `npm publish --dry-run` with
no `if:` guard. `npm publish --dry-run` contacts the registry and
exits 1 with "You cannot publish over the previously published
versions" when the target version exists.
The earlier `Detect prior publish (reconciliation mode)` step already
discovers this case and sets steps.prior_publish.outputs.skip_publish=true.
The actual publish step (further down) is gated on that. The
rehearsal step was missing the gate, so any re-run of an
already-published hotfix blew up at the rehearsal before reaching
the reconciliation logic — exactly when an operator is trying to
recover from a later-step failure (merge-back, summary, etc.).
Add `if: ${{ steps.prior_publish.outputs.skip_publish != 'true' }}`
matching the publish step's gate. The rehearsal still runs on first
publishes where it has value.
Trigger: run 25233855236.
Closes#2987
