Preserve intermediate wrapped functions in stacked decorators

[jakezwang]

Set __wrapped__ after copying the wrapped function's attributes, so stacked decorators retain the immediate wrapper instead of skipping a layer. Apply the same ordering to decorator factories whose caller is already wrapped.

Add regressions for one-layer bypass, inspect.unwrap, and wrapped callers.

Earlier validation: 28 tests and 118 doctests on Python 3.8–3.14; flake8 and codespell passed. After the conditional-wrapper update, source mypy and stubtest pass on Python 3.14. A fresh Python 3.11 stubtest run is blocked by the unchanged stub file importing annotationlib, which is not available on that Python version.

[micheles]

Thanks for your contribution, but I see a small issue with the stubtest; can you check that?