I would say that is the right code, but it is a dubious request by the journal editor and the endpoints of a 95% interval are not estimated particularly accurately with the default number of draws.
The values for the POV are approximately median 0.27 (0.26, 0.28).
I would have thought that that number of draws would be sufficient for accurate estimation of the endpoints.
Also, the Bayesian R2 for the model is 0.42.
I have a more philosophical question. I have been convinced from the expositions by you and Gelman and others that I should move from null hypothesis testing to parameter estimation.
In the medical journals (anesthesia) where I publish, Bayesian analyses are very rare.
I will probably have to add the factor POV that has been requested. But what are the main points with which I should argue against this request?