`nimbleHMC` needs `userEnv` argument

[paciorek]

This needs to mimic what we now have in nimbleMCMC as of June 2025 on devel. Critically, userEnv needs to be passed along to mcmc_createModelObject or that will fail as it has no default value for userEnv.

Once nimble 1.4.0 goes up, nimbleHMC::nimbleHMC will be broken, so I think we want this staged to be released right after I submit nimble 1.4.0.

If we release nimbleHMC before nimble, then it will also be broken as nimble::mcmc_createModelObject in current nimble 1.3.0 won't be expecting the userEnv argument.

Based on my reverse dependency check, I don't think this will visible to CRAN.

I guess this also means that nimbleHMC 0.2.4 requires nimble 1.4.0.

[danielturek]

@paciorek This is addressed in PR #80.

We can return to this, following the release of nimble 1.4.0