Add missing runtime dependencies

[charles-openclaw]

Summary

• Add the runtime dependencies imported by the package to pyproject.toml so a vanilla pip install . environment installs them.
• Add pyyaml to .conda/environment.yml to cover the YAML dependency called out in Dependencies not installed but default with the package #13.

Fixes #13.

Verification

• Reproduced on current main: uv pip install . in a fresh Python 3.12 env succeeded, then python -c "import metplan.metplan" failed with ModuleNotFoundError: No module named 'yaml'.
• After the change: fresh Python 3.12 uv env, uv pip install . pytest, then python -c "import metplan.metplan; import yaml, h5py; print(yaml.__version__, h5py.__version__)" passed and printed 6.0.3 3.16.0.
• git diff --check -- pyproject.toml .conda/environment.yml passed.
• python -m pytest tests ran 58 tests: 57 passed; tests/test_metplan.py::test_sample_dataset failed because the test config writes to /scratch/tm70/ag9761/met_data/..., which does not exist in this contributor environment.