Cookwala ROS 2 interfaces

cookwala_msgs is a ROS 2 interface package (ament_cmake) with two actions that mirror the Core 0.2 API:

Action	Goal	Feedback	Result
`ExecuteRecipe`	`ExecuteRequest` (recipe ref, hash, servings, idempotency key, full request JSON)	`ExecutionStatus` fields (seq, state, node, op, progress, rung, medium temperature, human needed)	final state, refusal reason, `ExecutionLog` JSON
`ExecuteNode`	one recipe node, its envelope, an optional narrower target	progress, medium temperature, target reached	envelope ok, rung used, step summary, deviation

Cancelling a goal is a StopRequest: the server must stop safely. Safety limits are enforced by the device; nothing in a goal can change them.

bash

# in a ROS 2 workspace
ln -s /path/to/cookwala/bindings/ros2/cookwala_msgs src/cookwala_msgs
colcon build --packages-select cookwala_msgs
ros2 interface show cookwala_msgs/action/ExecuteRecipe

JSON fields are carried as strings so the ROS 2 types never drift from the schemas; validate them with the published bundle at https://cookwala.ai/v1/schemas/bundle.json (generated by tools/build_site.sh). The package is not yet built in CI. A bridge node that maps these actions to the HTTP Core API (the reference hub in hub/) is a good first contribution; see docs/ROBOTICS.md.