Contributing

Setting up the environment

bash scripts/setup_env.sh
source .venv/bin/activate

Recommended workflow

Create a branch off main: git checkout -b feat/my-feature.
Write code and add tests in tests/.
Run quality checks before pushing:
```
ruff check src tests
mypy src
pytest
```
Rebuild the docs and check that they compile without warnings:
```
cd docs && make clean html
```

Conventions

Magnetic sign convention: H = +Σ_{i≠j} J_ij S_i·S_j (AFM > 0).
Type hints are required on the public API.
Docstrings in Google or NumPy style (Napoleon accepts both).
ruff settings: 100-char line length, rules E F W I N UP B C4 SIM.
Unit tests for every new feature or bug fix.
Physics-style names (JS2, Jq, q_cart) are allowed — ruff ignores N803 and N806.