fix unit test workflow for forks

Author: nicktrn

.github/workflows/unit-tests.yml

@@ -7,6 +7,8 @@ jobs:
   unitTests:
     name: "🧪 Unit Tests"
     runs-on: ubuntu-latest
+    env:
+      DOCKERHUB_USERNAME: ${{ secrets.DOCKERHUB_USERNAME }}
     steps:
       - name: 🔧 Disable IPv6
         run: |
@@ -52,10 +54,14 @@ jobs:
 
       # ..to avoid rate limits when pulling images
       - name: 🐳 Login to DockerHub
+        if: ${{ env.DOCKERHUB_USERNAME }}
         uses: docker/login-action@v3
         with:
           username: ${{ secrets.DOCKERHUB_USERNAME }}
           password: ${{ secrets.DOCKERHUB_TOKEN }}
+      - name: 🐳 Skipping DockerHub login (no secrets available)
+        if: ${{ !env.DOCKERHUB_USERNAME }}
+        run: echo "DockerHub login skipped because secrets are not available."
 
       - name: 📥 Download deps
         run: pnpm install --frozen-lockfile