zope.event==5.1 installed without dist-info metadata, causing DistributionNotFound error

## BUG/PROBLEM REPORT / FEATURE REQUEST

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### What I did:

I installed `zope.event==5.1` in a Docker environment based on `python:3.10`.
After installing all dependencies, I started a Flask application using Gunicorn with the gevent worker:

```bash
gunicorn -k gevent -w 1 -b 0.0.0.0:5000 run:app
```

During worker initialization, gevent calls `monkey.patch_all()` internally, which attempts to load entry points and requires the `zope.event` distribution.

### What I expect to happen:

I expected `zope.event==5.1` to be installed with all necessary metadata (`dist-info`) and module files so that `pkg_resources` could recognize and load the distribution without any error.

### What actually happened:

After installing `zope.event==5.1`, the package directory only contained a `.pth` file:

```plaintext
/usr/local/lib/python3.10/site-packages/zope.event-5.1-py3.12-nspkg.pth
```

There was no `dist-info` directory and no actual `zope/event/__init__.py` module.
As a result, when running Gunicorn with gevent, I consistently get this error:

```plaintext
pkg_resources.DistributionNotFound: The 'zope.event' distribution was not found and is required by the application
```

Downgrading to `zope.event==5.0` immediately resolved this issue, and the proper metadata files were installed.

### What version of Python and Zope/Addons I am using:

- Operating System: Debian (Docker python:3.10)
- Python: 3.10.18
- zope.event: 5.1 (problematic), 5.0 (working)
- gevent: 22.10.2
- gunicorn: 20.1.0
- Flask: 3.1.0

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