admixr2 0.1.0

• Initial release.
• Monte Carlo estimator (est = "admc") via admControl().
• Iterative Reweighting Monte Carlo estimator (est = "adirmc") via adirmcControl().
• Analytical CRN gradient with sensitivity equations (grad = "sens").
• Multi-restart parallelism via furrr/future.
• Diagnostic plots: observed vs predicted mean/covariance, NLL trace, parameter trace.
• Integrates with the nlmixr2/rxode2 ecosystem.