Add tests for both Go and Python ServeHTTP implementations covering:
- Body chunking behavior (small, exact, multiple, large bodies)
- Context cancellation during body streaming
- Header conversion utilities
- HTTPRequest/HTTPResponseWriter helper classes
- Request body assembly from multiple chunks
- Error handling (500 for handler errors, 404 for missing handler)
Go tests:
- TestChunking_* for body chunking scenarios
- TestConvertHTTPHeaders for header conversion
- TestBuildRequestInit for request metadata building
- TestWriteResponseHeaders for response header writing
- TestContextCancellation_DuringBodyRead for cancellation
Python tests:
- TestHTTPRequest for request wrapper class
- TestHTTPResponseWriter for response writer class
- TestHeaderConversion for proto<->dict conversion
- TestServeHTTPServicer for gRPC servicer behavior
- TestChunkingBehavior for body assembly
- TestCancellation for request cancellation
Also:
- Fixed sendRequest to properly set body_complete flag on EOF
- Added ServeHTTP to HookName enum
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>