Update pipeline-eval.yml with working configuration

- Add PyTorch installation step
- Use workdir: /workdir for artifact accessibility
- Copy result.json to workdir before container exits
- Activate venv before running evaluation

Author: Mark Saroufim

deployment/buildkite/pipeline-eval.yml

@@ -49,9 +49,14 @@ steps:
       echo "=== Installing Dependencies ==="
       uv sync
 
+      echo ""
+      echo "=== Installing PyTorch ==="
+      uv pip install torch triton numpy --index-url https://download.pytorch.org/whl/cu124
+
       echo ""
       echo "=== Running Evaluation ==="
-      uv run python src/runners/buildkite-runner.py
+      . .venv/bin/activate
+      python src/runners/buildkite-runner.py
 
       echo ""
       echo "=== Copying Artifacts ==="