Implement asynchronous HTTP request infrastructure for the Wren scripting language, including a thread pool with 4 worker threads, request/response queue management, and foreign function bindings for Wren callbacks. Add Response class with foreign methods for error status, status code, body, and JSON access. Include Requests class with static get/post methods that validate callback arity and delegate to foreign implementations. Integrate libcurl-based backend with thread-safe queue operations and platform-specific threading primitives (pthreads on Unix, Windows threads on Win32). Add Makefile targets for building the wren executable with libcurl, pthread, and math library dependencies.
