Add compat bounds for direct stdlib dependencies

[ChrisRackauckas-Claude]

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

What changed and why

Add compat bounds for the direct Pkg, REPL, and Test standard-library dependencies. Aqua's dependency-compat audit currently rejects SciMLTesting because all three are listed in [deps] without corresponding [compat] entries. A package test now protects this metadata invariant.

The "1.10" bounds match SciMLTesting's minimum supported Julia version and permit later 1.x stdlib releases.

Verification

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

Test Summary:         | Fail  Total  Time
stdlib compat entries |    3      3  4.0s
ERROR: Package SciMLTesting errored during testing

Passing after the fix:

Test Summary:         | Pass  Total  Time
stdlib compat entries |    3      3  0.0s
Test Summary: | Pass  Total     Time
SciMLTesting  |  434    434  1m37.3s
Testing SciMLTesting tests passed

The focused Aqua self-audit also passes:

Test Summary:     | Pass  Total   Time
Quality Assurance |   11     11  27.6s

Commands:

julia +release --project=. --startup-file=no -e 'using Pkg; Pkg.test()'
julia +release --project=. --startup-file=no -e 'using SciMLTesting; run_qa(SciMLTesting; JET = nothing, explicit_imports = false, api_docs = false, check_reexports = false)'
julia +release --startup-file=no -m Runic --check test/runtests.jl
typos Project.toml test/runtests.jl
git diff --check

The unfiltered self-audit now records 17 passing checks and three pre-existing ExplicitImports errors, versus 16 passes, one dependency-compat failure, and the same three errors on main. The remaining dynamic-include analyzability and non-public qualified-access findings are independent and are not changed here.

Docs were not built because this PR only changes dependency metadata and its regression test.

🤖 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: 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/33859228290