feat: add AGENTS.md

Author: kosiew

AGENTS.md

@@ -0,0 +1,42 @@
+# Repository instructions for datafusion-python
+
+## Style and Linting
+- Python formatting and linting is handled by **ruff**.
+- Rust code must pass `cargo fmt`, `cargo clippy`, and `cargo tomlfmt`.
+- Install the pre-commit hooks with `pre-commit install` and run them with
+  `pre-commit run --files <file1> <file2>` or `pre-commit run --all-files`.
+- The same checks can be run manually using the scripts in `ci/scripts`:
+  - `./ci/scripts/python_lint.sh`
+  - `./ci/scripts/rust_fmt.sh`
+  - `./ci/scripts/rust_clippy.sh`
+  - `./ci/scripts/rust_toml_fmt.sh`
+
+## Running Tests
+1. Ensure submodules are initialized:
+   ```bash
+   git submodule update --init
+   ```
+2. Create a development environment and install dependencies:
+   ```bash
+   uv sync --dev --no-install-package datafusion
+   ```
+3. Build the Python extension:
+   ```bash
+   uv run --no-project maturin develop --uv
+   ```
+4. Execute the test suite:
+   ```bash
+   uv run --no-project pytest -v .
+   ```
+
+## Building Documentation
+- Documentation dependencies can be installed with the `docs` group:
+  ```bash
+  uv sync --dev --group docs --no-install-package datafusion
+  ```
+- Build the docs with:
+  ```bash
+  uv run --no-project maturin develop --uv
+  uv run --no-project docs/build.sh
+  ```
+- The generated HTML appears under `docs/build/html`.