Support generating transect output with TempestRemap

@charleskawczynski asked for these diagnostic outputs in the meeting today:

See: https://github.com/ClimateGlobalChange/tempestremap/blob/master/src/GenerateTransectMesh.cpp

Start with the linked TempestRemap src/GenerateTransectMesh.cpp to understand the requested diagnostic outputs, then locate the corresponding transect-generation entry point in ClimaCore.jl. The issue does not name repository files or specify which outputs are required, so confirm the output contract before implementation; done means the requested transect diagnostics can be generated.

Written by the indexing model from the issue text.