Add HF_TOKEN environment variable to test workflow

- Set HF_TOKEN from secrets for dependency installation and tests
- Enables access to HuggingFace models during CI if needed

.github/workflows/tests.yml

@@ -39,10 +39,14 @@ jobs:
         cache-dependency-glob: "uv.lock"
 
     - name: Install dependencies
+      env:
+        HF_TOKEN: ${{ secrets.HF_TOKEN }}
       run: |
         uv sync
 
     - name: Run tests with coverage
+      env:
+        HF_TOKEN: ${{ secrets.HF_TOKEN }}
       run: |
         make test-coverage