refactor(protocol): move wire helpers into canonical protocol module

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>

include/cvmmap_streamer/protocol/wire_codec.hpp

@@ -6,7 +6,7 @@
 
 #include "cvmmap_streamer/ipc/contracts.hpp"
 
-namespace cvmmap_streamer::sim {
+namespace cvmmap_streamer::protocol::wire_codec {
 
 constexpr std::size_t kSyncMessageBytes         = 48;
 constexpr std::size_t kModuleStatusMessageBytes = 32;