…tors

Preserve one-shot operation iterators during patch validation

…etup

Clean temporary output after fdopen setup failure

- Run flake8 in a separate lint job: syntax errors and undefined names
  fail the build, everything else is reported as a warning.
- Build sdist/wheel and run `twine check --strict` on every push/PR,
  not only at release time.
- Build the Sphinx docs with warnings as errors.
- Test on PyPy 3.10/3.11, matching the PyPy classifier.
- Test on Windows and macOS (Python 3.13), matching "OS Independent".
- Install test dependencies from requirements-dev.txt.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ASUFowntPRr2bsnKLwY3DB

Current hypothesis releases build a PyO3 extension, and PyO3 requires
PyPy >= 3.11, so installing the test dependencies fails on PyPy 3.10.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ASUFowntPRr2bsnKLwY3DB

Extend CI: lint, package build, docs build, PyPy, Windows/macOS