PYTHON-5839 - PyMongo wheels have multiple versions of C extensions

[NoahStapp]

PYTHON-5839

Changes in this PR

Clean up built C extensions after each version to prevent them from leaking into the next wheel.

Test Plan

Tested with dist CI checks.

Checklist

Checklist for Author

• [ ] Did you update the changelog (if necessary)?
• [ ] Is there test coverage?
• [ ] Is any followup work tracked in a JIRA ticket? If so, add link(s).

Checklist for Reviewer

• Does the title of the PR reference a JIRA Ticket?
• Do you fully understand the implementation? (Would you be comfortable explaining how this code works to someone else?)
• Is all relevant documentation (README or docstring) updated?

[Copilot]

Pull request overview

This PR addresses PYTHON-5839 by ensuring in-place built C extension artifacts don’t persist between cibuildwheel builds for different Python versions, preventing multiple extension versions from being unintentionally included across wheels.

Changes:

• Replace the old targeted cleanup logic with a generic cleanup that removes *.so and *.pyd artifacts from bson/ and pymongo/.
• Configure cibuildwheel via CIBW_BEFORE_BUILD in the dist workflow to run the cleanup before each wheel build.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
tools/clean.py	Simplifies cleanup by deleting any *.so/*.pyd under bson and pymongo before each build.
.github/workflows/dist.yml	Adds CIBW_BEFORE_BUILD hook so cleanup runs before each cibuildwheel build iteration.

[NoahStapp]

Old output:

# in wheel's bson/ directory
_cbson.cpython-39-aarch64-linux-gnu.so
_cbson.cpython-310-aarch64-linux-gnu.so
_cbson.cpython-311-aarch64-linux-gnu.so
_cbson.cpython-312-aarch64-linux-gnu.so
_cbson.cpython-313-aarch64-linux-gnu.so
_cbson.cpython-314-aarch64-linux-gnu.so

New output:

# in wheel's bson/ directory
_cbson.cpython-39-x86_64-linux-gnu.so

[codecov-commenter]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[blink1073]

LGTM