docs: improve repo layout and checks

README.md

@@ -149,7 +149,7 @@ through thin [`pyo3`](https://pyo3.rs/) bindings.
 │   ├── tests.rs          # Canonical Rust test-suite
 │   └── py_module.rs      # PyO3 bindings ⇒ compiled as openai_harmony.*.so
 │
-├── harmony/              # Pure-Python wrapper around the binding
+├── python/openai_harmony/ # Pure-Python wrapper around the binding
 │   └── __init__.py       # Dataclasses + helper API mirroring chat.rs
 │
 ├── tests/                # Python test-suite (1-to-1 port of tests.rs)

run_checks.sh

@@ -5,4 +5,5 @@ set -e
 cargo fmt --check
 cargo clippy --all-targets --all-features -- -D warnings
 cargo test --all-targets --all-features
-
+mypy python/openai_harmony
+ruff check .