Publishing to PyPI from CI is enabled for this repository.

`release.yml` reads only whether this file exists. Its contents are for a human.

WHAT HAD TO BE TRUE BEFORE THIS FILE COULD EXIST, and what breaks if either is
undone:

  1. A GitHub environment named `pypi`, with a required reviewer. The publish
     job names that environment, so every upload waits for a person. Delete the
     environment and the job fails at start rather than uploading unreviewed.

  2. A PyPI trusted publisher on `arbiter-engine` naming this repository, the
     workflow file `release.yml`, and the `pypi` environment. No API token is
     stored anywhere; the index mints a short-lived one per run. Remove the
     publisher and the job fails to authenticate.

Both are settings, not code, so neither shows up in a diff. That is why this
file says what they are: a reader who finds the publish job enabled can check
the two things it depends on without guessing.

To hand publishing back to a person, delete this file. The release job still
builds the distributions from the tag and attaches them to the Release; only the
upload stops.
