Fits a wide variety of multivariate spatio-temporal models
with simultaneous and lagged interactions among variables (including
vector autoregressive spatio-temporal ('VAST') dynamics)
for areal, continuous, or network spatial domains.
It includes time-variable, space-variable, and space-time-variable
interactions using dynamic structural equation models ('DSEM')
as expressive interface, and the 'mgcv' package to specify splines
via the formula interface. See Thorson et al. (2025)