Call for testers: v3.0.0-beta.1 (thin wrapper around game-ci/cli)

We just cut [`v3.0.0-beta.1`](https://github.com/game-ci/unity-activate/releases/tag/v3.0.0-beta.1) — a preview of the next major version of `unity-activate`, rewritten as a thin wrapper around [`game-ci/cli`](https://github.com/game-ci/cli) (see [#111](https://github.com/game-ci/unity-activate/pull/111) for the full technical writeup). It's tagged separately from `@v2`/`@v1` — nobody's existing workflow is affected by this.

Before we cut the real `v3`, we'd like people to actually try it. It's had unit tests and local checks, but not a live runner with real Unity credentials.

## How to try it

Point one workflow (or a copy of one) at the pre-release tag, and pin `cliVersion` explicitly so your run is deterministic:

```yaml
- uses: game-ci/unity-activate@v3.0.0-beta.1
env:
UNITY_EMAIL: ${{ secrets.UNITY_EMAIL }}
UNITY_PASSWORD: ${{ secrets.UNITY_PASSWORD }}
with:
cliVersion: v0.1.8
```

Everything else — secrets, license type — stays the same as `@v2`. Both personal and professional license activation are useful to hear about.

## Known gaps already called out (not surprises)

- `unityVersion` is accepted for backward compatibility but no longer does anything — the CLI auto-detects from `ProjectSettings/ProjectVersion.txt`.

Full list in the [release notes](https://github.com/game-ci/unity-activate/releases/tag/v3.0.0-beta.1).

## What to report here

- Did activation succeed/fail, and how did that compare to `@v2`?
- Personal or professional license, and runner OS you tested with.
- Anything that felt different, even something minor.

Thanks for helping get this solid before it ships as the default. 🙏

---

### Ready-to-post Discord announcement

If you're active in the [GameCI Discord](https://discord.gg/game-ci) and want to help spread the word, here's a copy-pasteable version for the announcement/help channel:

```
Hey folks! We just cut a pre-release of the next major `unity-activate` version — v3.0.0-beta.1. It's a rewrite as a thin wrapper around game-ci/cli instead of the action doing activation itself. Tagged separately from @v2, so it won't touch anyone's existing workflows.

If you've got a spare few minutes, we'd love for you to try it before the real v3 ships:

- uses: game-ci/unity-activate@v3.0.0-beta.1
env:
UNITY_EMAIL: ${{ secrets.UNITY_EMAIL }}
UNITY_PASSWORD: ${{ secrets.UNITY_PASSWORD }}
with:
cliVersion: v0.1.8

Everything else stays the same as @v2 - just swap the tag and add cliVersion so your run is deterministic. Known gap: unityVersion is now ignored (auto-detected from ProjectSettings/ProjectVersion.txt instead).

Report back in the tracking issue: https://github.com/game-ci/unity-activate/issues/112

Thanks for helping kick the tires! 🙏
```

Start with the workflow example in the issue and the v3.0.0-beta.1 release notes; run a copied workflow using the pre-release tag and an explicit cliVersion. Done means reporting whether activation succeeded or failed, the license type and runner OS, and any differences from @v2.

Written by the indexing model from the issue text.