VARcheck 0.1.0

• Initial CRAN release.
• new_var_data(): constructs a model-agnostic var_data object from empirical data, predictions, residuals, and optional simulated data. Accepts a single matrix (single subject) or a list of matrices (multiple subjects).
• plot_var_check(): assembles a multi-panel diagnostic grid — one row per variable — with empirical vs. predicted time series, residual inspection, a residuals vs. predictions scatter, and optional posterior predictive check panels.
• theme_varcheck(): default minimal ggplot2 theme used by plot_var_check(), available for standalone use.