compat: declare SciMLTesting 2.10

[ChrisRackauckas-Claude]

Summary

Raise the root package's SciMLTesting compatibility declaration to 2.10 and keep the existing documentation doctests bounded by using small explicit epoch counts in the training examples. The public API documentation, transform interface tests, and LuxTestUtils test setup are already present on the current main base through #156; this PR does not duplicate them.

No library runtime behavior is changed.

Verification

• GROUP=Core julia --startup-file=no --project=. -e 'using Pkg; Pkg.test()': Fourier Neural Operator 14/14, DeepONet 10/10, NOMAD 10/10, SpectralConv 12/12, SpectralKernel 14/14, Transform Interface 15/15.
• GROUP=QA julia --startup-file=no --project=. -e 'using Pkg; Pkg.test()': Aqua/ExplicitImports 21/21; doctests 1/1.
• julia --startup-file=no --project=docs docs/make.jl: doctests, cross-references, document checks, population, rendering, and HTML completed successfully.
• Runic check, typos, and git diff --check passed.

The local docs build emitted only large HTML representation warnings and the expected local deployment autodetect warning. GPUCore, Windows, and downstream jobs were not run locally.

Please ignore this draft until reviewed by @ChrisRackauckas.

[ChrisRackauckas-Claude]

Clean-base comparison completed: PR #158 and current main both fail the affected Core lanes with Reactant 0.2.279 / Reactant_jll 0.0.404+1 and lld: error: undefined symbol: jl_cstr_to_string during Reactant precompilation. The PR does not modify test/Project.toml; its only change is the SciMLTesting compat declaration. Historical main passed with Reactant 0.2.278, so this is an upstream Reactant/Windows regression rather than a QA compat regression.

Probe evidence: https://github.com/SciML/NeuralOperators.jl/actions/runs/31919259681/job/95097672584

[ChrisRackauckas-Claude]

Correction to the previous comment: the hosted Core failures report lld: error: undefined symbol: jl_cstr_to_string while loading Reactant. A clean-base probe reproduces this with the current Reactant resolution; historical base passed with the prior Reactant version. I am not adding a package pin or weakening tests in this QA/docs PR.