reviser 0.2.0

Bug fixes

summary() on a long-format tbl_pubdate no longer fails with “character string is not in a standard unambiguous format”. The method assumed a wide layout and treated the pub_date and value column names as publication dates, so it failed on every get_revisions() result. The reported number of time periods and vintages was also wrong for long input.
print() and summary() on a kk_model now report which specification was estimated. model = "Howrey" and model = "Classical" previously produced identical headers, because the fitted object never recorded the model argument. jvn_model objects likewise report whether news, noise or both were estimated.

kk_model and jvn_model objects gain the standard extractor methods: coef(), vcov(), logLik(), nobs(), fitted(), residuals() and predict(). AIC() and BIC() therefore work, and reproduce the values shown by summary().
New states() generic to access the estimated state paths of a fitted revision model, replacing direct use of fit$states.
New validate_vintages() checks a tbl_pubdate or tbl_release object against the documented class contract. See ?"reviser-vintages-classes" for the contract itself.

Covariance matrices are obtained through a Cholesky factorization, which exploits the symmetry of the Hessian and reports when it is not positive definite instead of silently applying a ridge. Delta-method transformations exploit the diagonal structure of the Jacobian, and the Kalman recursions use tcrossprod(). Estimates are unchanged.

Updated repository, issue tracker, and documentation links to the rOpenSci organization and docs site.
Updated package documentation and README badges to use rOpenSci URLs.
Added rOpenSci R-universe installation instructions to the README.
Removed the package-specific code of conduct file in favor of the rOpenSci project-wide code of conduct.
Disabled automatic pkgdown deployment to GitHub Pages and replaced the legacy website with a redirect page.