Make generated group includes statically analyzable

[ChrisRackauckas-Claude]

Please ignore this draft until it has been reviewed by @ChrisRackauckas.

What changed and why

Construct the generated group-body include call directly as an expression instead of quoting an interpolated call. The old source spelling looked like a runtime-dependent include to ExplicitImports, so it correctly refused to recurse into SciMLTesting and both source-analysis checks errored with UnanalyzableModuleException.

The resulting expression still contains the same literal path when evaluated by @safetestset. Once the source became analyzable, the stale @safetestset import was exposed and removed; the macro is referenced through its owning SafeTestsets module. A package test now runs both real source-analysis checks.

Verification

Failing before the fix, with the new test applied to f5884b6:

Test Summary:                     | Error  Total  Time
SciMLTesting source analyzability |     2      2  4.2s
ERROR: Package SciMLTesting errored during testing

Passing after the fix:

Test Summary:                     | Pass  Total  Time
SciMLTesting source analyzability |    2      2  1.9s
Test Summary: | Pass  Total     Time
SciMLTesting  |  436    436  1m19.3s
Testing SciMLTesting tests passed

Julia 1.10 LTS:

Test Summary:                     | Pass  Total  Time
SciMLTesting source analyzability |    2      2  1.5s
Test Summary: | Pass  Total     Time
SciMLTesting  |  420    420  1m10.1s
Testing SciMLTesting tests passed

Commands:

julia +release --project=. --startup-file=no -e 'using Pkg; Pkg.test()'
julia +lts --project=. --startup-file=no -e 'using Pkg; Pkg.test()'
julia +release --project=. --startup-file=no -e 'using SciMLTesting; run_qa(SciMLTesting; JET = nothing)'
julia +release --startup-file=no -m Runic --check src/SciMLTesting.jl test/runtests.jl
typos src/SciMLTesting.jl test/runtests.jl
git diff --check

The unfiltered self-audit improves from 16 passes, one failure, and three errors on main to 18 passes, one failure, and one error. The remaining stdlib-compat failure is addressed independently in #64; the non-public qualified-access findings are a separate concern and are not hidden here.

Docs were not built because no docstrings, documentation pages, or public API changed.

🤖 Generated with Codex CLI 0.151.0 (model: gpt-5.6-sol; session: local session ID 01a0598f-11b9-72d1-91d9-b2fbb186557d)

[ChrisRackauckas-Claude]

Final CI audit after the test-placement amendment: all 12 required checks passed, including Julia 1/LTS/pre-release on Linux, macOS, and Windows, downgrade, Runic, and spelling. Test matrix: https://github.com/SciML/SciMLTesting.jl/actions/runs/33860723000