Module protocol 

Protocol definitions for client-server communication

The protocol uses two channels:

• Data channel: Raw bytes, no framing (stdin→server, server→stdout)
• Control channel: JSON messages for out-of-band communication

Structs

ClientHello

Client hello message sent during handshake

FileRequest

A file to open with optional line/column position, range, and hover message

ServerHello

Server hello message sent in response to ClientHello

TermSize

Terminal size in columns and rows

VersionMismatch

Version mismatch error response

Enums

ClientControl

Control messages from client to server

ControlMessage

Wrapper for control channel messages (used for JSON serialization)

ServerControl

Control messages from server to client

Constants

PROTOCOL_VERSION

Protocol version - must match between client and server

Functions

read_control_message

Read a JSON control message from a reader

write_control_message

Write a JSON control message to a writer