Block fork pull request workflow jobs

Author: CodeRabbit Automation

.github/workflows/openai-review.yml

@@ -18,6 +18,7 @@ concurrency:
 
 jobs:
   review:
+    if: ${{ github.event.pull_request == null || github.event.pull_request.head.repo.full_name == github.repository }}
     runs-on: ubuntu-latest
     steps:
       - uses: fluxninja/openai-pr-reviewer@main