ci: add uv_exclude_newer env in github actions workflow?

Nobody has claimed this yet.

You are now using `uv` in ci as well. uv offers dependency cooldowns, of X days or weeks within the publication of a new package version. This can be enabled via an env like this in ci:

```yaml
env:
UV_EXCLUDE_NEWER: 1 week # ignore packages published in the last week
```

or directly in `pyproject.toml`, which then will apply to dev work as well:

```toml
[tool.uv]
exclude-newer = "1 week"
```

This way there is a slimmer chance of a bad package hitting ci and/or dev machines. What do you think?

Ref: https://docs.astral.sh/uv/concepts/resolution/#dependency-cooldowns

Start by locating the GitHub Actions workflow that uses uv and read how its environment is configured. Apply the proposed dependency cooldown in CI, then run or inspect the workflow to confirm that the setting is accepted and affects dependency resolution.

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