fix(core): resolve annotations for tools wrapped across modules

[fhgffy]

Why are these changes needed?

A tool decorated with functools.wraps can raise NameError during registration when its string annotations refer to names in the original function's module. inspect.signature follows the wrapped function, but passing the wrapper's globals to typing.get_type_hints resolves those annotations in the wrong namespace.

Let get_type_hints select the defining namespace in both signature and return-type resolution. The regression tests cover undecorated functions, one wrapper, nested wrappers, schema generation, and an actual FunctionTool.run_json call with a datetime argument.

Validation:

• The new tests against the original implementation: 8 failed, 4 passed; the failures reproduce the namespace error.
• The new tests plus existing tool and workbench tests: 60 passed.
• Ruff lint/format, mypy, and pyright passed using the repository's pinned versions.

Related issue number

Related to #8302, which addresses globals for partial functions. This change also covers ordinary and nested wrappers across modules, including return-type resolution.

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. No documentation changes are needed for this bug fix.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed. Local checks passed; GitHub checks are pending.

[fhgffy]

@microsoft-github-policy-service agree

[fhgffy]

@microsoft-github-policy-service terminate

[fhgffy]

@microsoft-github-policy-service agree