Added a glmmTMB model backend for Gaussian (identity-link) models #19. All broad- and narrow-sense estimators (H2_*() / h2_*(), including Standard, Cullis, Oakey, Piepho, and Delta) are supported and reproduce the lme4 backend exactly. Non-Gaussian glmmTMB models fail with an informative error.
h2() and H2() now fail with an informative error for non-Gaussian lme4 models (e.g. glmer()) instead of a cryptic method-dispatch error #48.
Added narrow-sense heritability estimation through h2() and the h2_*() estimator functions for models with a known additive genetic covariance structure.
Added a consistent interface across broad-sense (H2()), narrow-sense (h2()), and their Standard, Cullis, Oakey, Piepho, and Delta estimators.
Added support for more complex asreml and lme4 random-effect structures, including known genomic relationship matrices and structured residuals.
Added richer heritable objects that retain the fitted model and calculation metadata for downstream methods.