Implement Phase 7: PyO3 Python bindings

[AlexMercedCoder]

Summary

Implements Phase 7 — Python bindings (PyO3) from the implementation plan: an async-friendly Python API for agents on top of the Rust core.

What was built

PyO3 module (maggraph::python, feature-gated):

• load_config(path) / open_index(root_path) — config + index access
• GraphIndex — list_nodes(), read_node(), traverse(from_id, depth, order)
• read_node_async() / traverse_async() — non-blocking via pyo3-async-runtimes + Tokio spawn_blocking
• Node, TraversalResult, TraversalNode — metadata, Markdown reports, to_dict()
• MagGraphError — Python exception mapped from Rust errors

Python package (python/):

• Maturin build (pyproject.toml, python-ext feature for wheels)
• Type stubs (__init__.pyi, py.typed)
• 8 pytest tests (sync + asyncio)
• examples/python_agent.py — sync + async demo

CI & docs

• New python CI job: maturin build, pytest, wheel artifact upload
• planning/PYTHON.md, updated PROGRESS.md (Phase 7 complete)

Try it

cd python
python -m venv .venv && source .venv/bin/activate
pip install maturin pytest pytest-asyncio
maturin develop --release --features python-ext
pytest -v
python ../examples/python_agent.py

Test plan

• cargo test --all (63 Rust tests)
• cargo clippy --all-targets -- -D warnings
• pytest — 8 Python tests pass
• examples/python_agent.py runs (sync + asyncio)

Next

Phase 8 — wire MCP scaffold to these bindings; polish SKILL.md generation.

Slack Thread