golang/protobuf ? reverse-engineered prompt

Build me a Go module that provides support for Protocol Buffers, with the same core pieces this project describes.

I want a proto package for working with generated messages, things like cloning, merging, equality checks, and binary and text serialization. I also want JSON support for protobuf messages, plus helpers for the common well known types like Any, Timestamp, Duration, Wrappers, Struct, and Empty. Include a protoc-gen-go command that can generate Go code from .proto files, along with the generated descriptor and plugin types it needs.

Please keep it compatible with the older github.com/golang/protobuf style API, but if it makes sense, use the newer protobuf Go module under the hood. Make it something that builds and tests cleanly, and if you need current protobuf toolchain details, look up the latest docs online.