Function finalize_scalar_elliptic_cartesian 

pub fn finalize_scalar_elliptic_cartesian(
    program: &KernelProgram,
    graph: &PortableRealizationGraph,
    target: Target,
) -> Result<(ScalarEllipticCartesianModel, FinalizedScalarEllipticCartesianProblem), Diagnostic>

Finalize one portable Cartesian scalar-elliptic realization for an independently selected linear execution adapter.

The graph owns numerical intent. target is the selected runtime binding; its host bound or device kind must match the graph, while a CUDA ordinal remains outside persisted numerical identity.

This is the default-assembly form of the explicit-assembly finalizer. It performs canonical lowering, plan validation, mesh construction, local-operator evaluation, constraint handling, and deterministic sparse finalization, but deliberately does not select or invoke a solver backend.

Errors

Preserves exact lowering, Realization, discretization, and assembly diagnostics.