v0.1.30-pre.67

preview: no change a person can see - the app is pre.66's. A screen test's held-send
driver now uses the one hold a session never releases, so the row it measures is no
longer re-queued and sent out from under it (#9696cdad): 50 of 50 samples failed with
the mechanism driven on main's shape, 0 of 75 on this one. No code, no behaviour and no
schema change.