RL Minesweeper – web assets

• inference.js: Encodes board state and runs ONNX policy in the browser.
• policy.onnx: Trained policy (not in repo). Generate it with:

  cd ../../rl-minesweeper && pip install -r requirements.txt && python train.py --preset beginner && python export_onnx.py --checkpoint checkpoints/best.pt
  

  This writes policy.onnx into this directory.