Fix claude-code-action CI failures

Use pull_request_target to ensure secrets are available, and pass
github_token explicitly to avoid the OIDC token exchange flow.
See anthropics/claude-code-action#649

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Author: joostjager

.github/workflows/claude-review.yml

@@ -18,6 +18,7 @@ jobs:
       - uses: anthropics/claude-code-action@v1
         with:
           anthropic_api_key: ${{ secrets.ANTHROPIC_API_KEY }}
+          github_token: ${{ secrets.GITHUB_TOKEN }}
           prompt: |
             REPO: ${{ github.repository }}
             PR NUMBER: ${{ github.event.pull_request.number }}