`gh aw compile` consistent actions/setup sha generation

`gh aw compile` emits `.github/workflows/agentics-maintenance.yml` without pinned sha for actions/setup, instead generates `uses: github/gh-aw/actions/setup@v0.50.3`. This differs from the other emitted actions/setup references which are emitted as 

```
uses: github/gh-aw/actions/setup@b70143d20a8292a3180986fa71533fdb8acb79e3 # v0.50.3
```