Replace Python script with native C++ library for type schema generation #56
Description
Summary
Type schema retrieval currently shells out to Python script (get_type_schema.py). This adds process overhead, requires Python runtime, and complicates error handling
Proposed solution (optional)
Use native ROS2 C++ introspection libraries (rosidl_typesupport_introspection_cpp) directly to generate JSON schema without external process calls.
Additional context (optional)
Reference: type_introspection.cpp - python3 subprocess call for schema generation