Unwrap AutoSpecialize through SciMLBase

[ChrisRackauckas-Claude]

What changed and why

Teach the public SciMLBase.unwrapped_f interface how to unwrap NonlinearSolveBase.AutoSpecializeCallable, and add a regression assertion alongside the wrapper construction tests.

The wrapper fallback removal in d3e1692 exposed a downstream failure in the archived SciMLNLSolve package: its nested ForwardDiff tag does not match the wrappers precompiled by NonlinearSolveBase. NonlinearSolveBase 2.19.0 passes that downstream test, while 2.20.0 and later fail. SciMLNLSolve can now unwrap through a documented public SciMLBase API instead of reaching into NonlinearSolveBase internals.

This PR should be ignored until reviewed by @ChrisRackauckas.

Verification

Failing before the fix on clean current master (f16755710), with the regression assertion applied:

NONLINEARSOLVE_TEST_GROUP=Core julia +release --project=lib/NonlinearSolveBase --startup-file=no -e 'using Pkg; Pkg.test()'
Test Summary:                                                                   | Pass  Fail  Total  Time
maybe_wrap_nonlinear_f wraps non-dual IIP array problems of any eltype or ndims |    4     1      5  3.7s
ERROR: Some tests did not pass: 4 passed, 1 failed, 0 errored, 0 broken.

Passing with this fix:

NONLINEARSOLVE_TEST_GROUP=Core julia +release --project=lib/NonlinearSolveBase --startup-file=no -e 'using Pkg; Pkg.test()'
Test Summary:                                                                   | Pass  Total  Time
maybe_wrap_nonlinear_f wraps non-dual IIP array problems of any eltype or ndims |    5      5  0.5s
...
Testing NonlinearSolveBase tests passed

NONLINEARSOLVE_TEST_GROUP=QA julia +release --project=lib/NonlinearSolveBase --startup-file=no -e 'using Pkg; Pkg.test()'
Test Summary: | Pass  Total   Time
QA            |   20     20  49.3s
Testing NonlinearSolveBase tests passed

I also applied the method to a checkout of NonlinearSolveBase 2.30.3 and developed that checkout into SciMLNLSolve. Its full test suite then passed:

Basic:      14/14
Autodiff:    1/1
FiniteDiff:  1/1

Other local checks:

julia +release --startup-file=no -m Runic --check .
# exited 0

typos lib/NonlinearSolveBase/src/autospecialize.jl lib/NonlinearSolveBase/test/runtests.jl
# exited 0

julia +release --project=docs --startup-file=no -e 'using Pkg; Pkg.instantiate()'
julia +release --project=docs --startup-file=no docs/make.jl
# exited 0 after doctests, examples, and HTML rendering

git diff --check
# exited 0

Not verified

I did not run the monorepo root/full Everything suite, GPU jobs, or downstream packages other than SciMLNLSolve. The docs build emitted its existing missing-docstring and output-size warnings but completed successfully.

The fix still needs a 2.30.x backport/release to affect SciMLNLSolve's currently resolvable dependency set. SciMLNLSolve itself is archived, so its public-API downstream adjustment cannot be submitted until the repository is unarchived.