fix(release): install hypothesis in cibuildwheel test env

[stffns]

Summary

The v0.10.0 tag build failed on every wheel-test step:

```
E ModuleNotFoundError: No module named 'hypothesis'
```

Cause: PR #50 added `tests/test_properties.py`, which imports
`hypothesis`, but `release.yml` still only installs `pytest` in
the cibuildwheel test env.

Four wheel jobs (ubuntu, ubuntu-arm, macos-14, windows) all fail at
the inner `pytest {project}/tests -q` step. The `publish` job is
gated on `needs: [build_wheels, build_sdist]`, so nothing was
published to PyPI.

Fix

```yaml
CIBW_TEST_REQUIRES: "pytest hypothesis>=6.100"
```

Mirrors `pyproject.toml`'s `[dev]` pin.

Recovery path

Once this PR merges:

1. Delete the v0.10.0 tag (both local and remote -- no wheels were
   published, so the retag is clean):
   ```bash
   git tag -d v0.10.0
   git push origin :refs/tags/v0.10.0
   ```
2. Re-tag v0.10.0 on the new main so the fixed workflow picks it up:
   ```bash
   git tag -a v0.10.0 -m "snapvec 0.10.0"
   git push origin v0.10.0
   ```

Both steps require Jay's explicit OK since they touch shared tag state.

Test plan

• `release.yml` still parses (yaml valid)
• CI green on this PR
• After merge + retag, wheels build successfully and publish to PyPI

[gemini-code-assist]

Note

Gemini is unable to generate a review for this pull request due to the file types involved not being currently supported.

[Copilot]

Pull request overview

Fixes the release workflow’s wheel test environment so cibuildwheel installs hypothesis, matching the project’s dev/test requirements and preventing tag builds from failing during pytest.

Changes:

• Update CIBW_TEST_REQUIRES in the release workflow to include hypothesis>=6.100.
• Align wheel-test dependencies with pyproject.toml’s [project.optional-dependencies].dev.

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