Approximate Bayesian Latent Variable Analysis // Implements approximate Bayesian inference for Structural Equation Models (SEM) using a custom adaptation of the Integrated Nested Laplace Approximation (Rue et al., 2009) doi:10.1111/j.1467-9868.2008.00700.x as described in Jamil and Rue (2026a) doi:10.48550/arXiv.2603.25690. Provides a computationally efficient alternative to Markov Chain Monte Carlo (MCMC) for Bayesian estimation, allowing users to fit latent variable models using the 'lavaan' syntax. See also the companion paper on implementation and workflows, Jamil and Rue (2026b) doi:10.48550/arXiv.2604.00671.