Rehome the wire serialization helpers under protocol ownership so the module name reflects its real role instead of simulator-era naming.
- rename sim/wire header to protocol/wire_codec
- rename sim/wire implementation to protocol/wire_codec
- keep behavior and byte layout unchanged
Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)
Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>
