Fix eager eval of non-Field broadcasts in calc_level_val

[imreddyTeja]

The finite difference evaluation on GPUs incorrectly handles broadcasts that are not <: AbstractFieldStyle when they are nested within another Broadcasted.

• Code follows the style guidelines OR N/A.
• Unit tests are included OR N/A.
• Code is exercised in an integration test OR N/A.
• Documentation has been added/updated OR N/A.

[Copilot]

Pull request overview

Fixes CUDA finite-difference eager evaluation so that nested Broadcasted expressions that are not field-style (<: AbstractFieldStyle) are no longer handled as if they were field broadcasts when computing calc_level_val.

Changes:

• Import AbstractFieldStyle for use in CUDA eager-eval dispatch.
• Narrow reconstruct_space_and_call_calc_level_val’s special-case dispatch to Broadcasted{<:AbstractFieldStyle} to avoid reconstructing placeholder spaces for non-field-style nested broadcasts.

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[Copilot]

Pull request overview

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

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[Copilot]

The Revise/include snippet in the header comment still references test_scalar_4.jl. This makes it harder to run this test directly; update it to point to test_scalar_17.jl (and keep the path consistent with other scalar tests).

Suggested change

	using Revise; include(joinpath("test", "MatrixFields", "matrix_fields_broadcasting", "test_scalar_4.jl"))
	using Revise; include(joinpath("test", "MatrixFields", "matrix_fields_broadcasting", "test_scalar_17.jl"))

[Copilot]

test_scalar_17.jl is only wired into the GPU broadcasting CI group. The CPU broadcasting group currently runs scalar_1–scalar_16, so this addition makes the CPU/GPU scalar test lists diverge. If this test is not truly GPU-only, consider adding a matching CPU step (or consolidating these lists) to keep coverage symmetric and avoid missing regressions on CPU.

Suggested change

	- label: "Unit: matrix field broadcasting (GPU)"
	key: unit_matrix_field_broadcasting_gpu_scalar_17
	command: "julia --color=yes --check-bounds=yes --project=.buildkite test/MatrixFields/matrix_fields_broadcasting/test_scalar_17.jl"
	env:
	CLIMACOMMS_DEVICE: "CUDA"
	agents:
	slurm_gpus: 1
	slurm_mem: 10GB

[dennisYatunin]

I've tested the changes in this branch against #2417. The end-to-end test breaks when that PR is rebased off main, but it works when that PR is rebased off this branch.