C++ RAII wrapper generator for WeaveFFI.
Produces an idiomatic weaveffi.hpp header (with move semantics,
std::optional, std::vector, exception-based error handling) plus a
CMakeLists.txt skeleton on top of the C ABI emitted by
weaveffi-gen-c. Implements
[LanguageBackend]; the shared driver bridges it into the generator
pipeline.