Add rclpy node generator

[lsy3]

Summary

• add an importable Python generator and thin CLI for producing rclpy base-node modules from NoDL documents
• expose generation through CMake and setup.py helpers
• support publishers, subscriptions, services, actions, lifecycle nodes, QoS, and typed parameters
• add focused unit fixtures plus a separate downstream package that validates the exported CMake interface with a real ROS pub/sub round trip
• include both Python generator packages in the existing five-distro CI matrix

Why

NoDL currently provides C++ generation but no equivalent reusable Python path. This adds the Python generator while keeping the generation core single-sourced and the downstream integration fixture separate from the production package.

The parameter dependency is intentionally limited to generate_parameter_library_py; the Python generator does not need the C++ umbrella package or its runtime stack.

Validation

• ROS Jazzy colcon build --packages-up-to nodl_generator_py test_nodl_generator_py --symlink-install
• ROS Jazzy colcon test --packages-select nodl_generator_py test_nodl_generator_py
• colcon result: 20 tests, 0 errors, 0 failures, 0 skipped
• generator unit suite: 17 passed
• generated pub/sub integration round trip: passed
• Ruff on source and generated outputs
• CMake lint, XML validation, and git diff --check

CI exercises Humble, Jazzy, Kilted, Lyrical, and Rolling.

[read-the-docs-community]

Documentation build overview

📚 nodl | 🛠️ Build #33892927 | 📁 Comparing 8dbdc44 against latest (54c6203)

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4 files changed

+ generating_python.html
± index.html
± roadmap.html
± schema.html