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

@@ -0,0 +1,38 @@
+#pragma once
+
+#include <cstdint>
+#include <span>
+#include <string_view>
+
+#include "cvmmap_streamer/ipc/contracts.hpp"
+
+namespace cvmmap_streamer::protocol::wire_codec {
+
+constexpr std::size_t kSyncMessageBytes         = 48;
+constexpr std::size_t kModuleStatusMessageBytes = 32;
+
+void write_frame_metadata(
+	std::span<std::uint8_t> metadata,
+	const ipc::FrameInfo &info,
+	std::uint32_t frame_count,
+	std::uint64_t timestamp_ns);
+
+void write_sync_message(
+	std::span<std::uint8_t> out,
+	std::string_view label,
+	std::uint32_t frame_count,
+	std::uint64_t timestamp_ns);
+
+void write_module_status_message(
+	std::span<std::uint8_t> out,
+	std::string_view label,
+	ipc::ModuleStatus status);
+
+void write_deterministic_payload(
+	std::span<std::uint8_t> out,
+	std::uint32_t frame_count,
+	std::uint16_t width,
+	std::uint16_t height,
+	std::uint8_t channels);
+
+}