Re-exports instantiate::stan_cmdstan_exists() so users (and vignettes)
have a single, package-friendly entry point to ask "is the CmdStan
toolchain available on this machine?". Useful for gating
cmdstanr / brms examples in CI environments where CmdStan is not
available.
has_cmdstan()Logical scalar.
has_cmdstan()
#> [1] TRUE