Set OMEGA_ARCH from the E3SM machine configuration

[grnydawn]

This PR sets OMEGA_ARCH from the E3SM machine configuration. In addition, it resolves issues caused by differences between E3SM coupled builds with and without EAMxx.

• Derive GPU backend from USE_CUDA, USE_HIP, USE_SYCL, or threading settings
• Forward Kokkos_ARCH_* and Kokkos_ENABLE_* options from KOKKOS_OPTIONS
• Fail GPU builds when no Kokkos architecture is configured
• Preserve EAMxx-provided Kokkos::kokkos when available
• Fix CASEROOT handling for coupled and standalone builds
• Handle bare and namespaced dependency targets safely
• Use EKAT to build Kokkos in coupled builds without EAMxx
• Add BUILD_CONFIG_TEST to verify OMEGA_ARCH matches the Kokkos execution space

Fix: #508

The following coupled test passed on PM-CPU, PM-GPU, and Chrysalis. Tests on Frontier and Aurora are still ongoing.

./create_newcase     \
    --case <casedir>     \
    --res T62_oQU240 \
    --compset COMEGA-IAF     \
    --driver mct    \
    --machine chrysalis     \
    --compiler intel  \
    --walltime 00:30:00  \
    --handle-preexisting-dirs r

A coupled test with --res TL319_EC30to60E2r2 --compset COMEGA-JRA1p5 looks good. It successfully passed both compilation and execution. However, the run ended prematurely due to the job allocation time limit on PM-CPU.

Checklist

• Documentation:

  • Design document has been generated and added to the docs
  • User's Guide has been updated
  • Developer's Guide has been updated

• Linting

  • Pre-commit run locally

• Building

  • CMake build does not produce any new warnings from changes in this PR

• Testing
  chrysalis, gnu, openmpi

  • CTests Pass
  • E3SM-Coupled C-case Pass

  pm-cpu, gnu, mpich

  • CTests Pass
  • E3SM-Coupled C-case Pass

  pm-gpu, gnugpu, mpich

  • CTests Pass
  • E3SM-Coupled C-case Pass

• New tests:

  • CTest unit tests for new features have been added per the approved design.