Correction, 30 September 2026. Technical wording rewritten in shorter sentences under the readability rule; the meaning is unchanged.
Correction, 20 October 2026. This text was reviewed after the study finished, in a catch-up of the earliest studies; the result, outcome and dates are unchanged.
Rules fixed before the result
The rules for each possible answer, and our own guess, were written down before any result was seen.
How it was made
Run took 20 minutes; independent code review: approve.
Exploratory work on development data; not a performance claim.