astronomix._geometry.boundaries

Ghost-cell boundary handling for the primitive state.

Fills the padded ghost-cell regions according to the configured per-axis boundary conditions: open (zero-gradient), periodic, reflective (normal velocity negated), fixed (Dirichlet, optionally open in the normal momentum) and the specialised 2D MHD jet-injection boundary. The top-level _boundary_handler dispatches per spatial axis; everything below it is a single traced branch on static configuration values, so no Python loops survive into the trace.