FIX: don't evaluate annotations when collecting signature parameters (Python 3.14 / PEP 649)

[mscheltienne]

Fix suggested by Claude Opus 4.8 on failures observed today while modernizing our SW stack to 3.14+.

On Python 3.14, PEP 649 evaluates annotations lazily and inspect.signature() now resolves them (VALUE format) when building the signature. As a result, running numpydoc validation on a callable whose signature annotation references a name that's only importable under TYPE_CHECKING raises NameError — a common pattern for typing-only imports, especially in modules that can't use from __future__ import annotations. Validator.signature_parameters guards inspect.signature() only against (TypeError, ValueError), so the NameError propagates and aborts the Sphinx build (the autodoc-process-docstring handler raises).

signature_parameters only uses parameter names and kinds, never the annotation values, so this evaluation is unnecessary. On Python 3.14+ it now introspects with annotationlib.Format.FORWARDREF, which returns unresolved forward references as ForwardRef objects rather than evaluating (and crashing on) them. Behaviour on Python < 3.14 is unchanged.

Reproducer (Python 3.14):

from typing import TYPE_CHECKING
if TYPE_CHECKING:
    from somewhere import Thing

def build() -> Thing: ...   # module does NOT use `from __future__ import annotations`

Validating build previously raised NameError: name 'Thing' is not defined; with this change it validates cleanly.

[mscheltienne]

@jarrodmillman @larsoner It would be appreciated if that fix can fit in the 1.11 release :)
Let me know if you want additional changes.

[larsoner]

Looks reasonable to me! Could you add a regression test? Maybe something like (suggested by Claude Opus 5):

@pytest.mark.skipif(sys.version_info < (3, 14), reason="PEP 649 lazy annotations")
def test_signature_params_with_typechecking_only_annotation():
    ns = {}
    exec("def func(a, b=1, *args, **kwargs) -> OnlyUnderTypeChecking: ...", ns)
    assert Validator(get_doc_object(ns["func"])).signature_parameters == (
        "a", "b", "*args", "**kwargs",
    )

[mscheltienne]

Done: 0d20d54

[larsoner]

Thanks @mscheltienne !