Codeoid wire protocol — Rust port of src/protocol/types.ts from the daemon.

This crate is pure data: no I/O, no async, no Tokio. It defines serde- compatible types for every message that flows between a Codeoid client and the daemon's WebSocket server.

Design notes

• Discriminated unions. TypeScript uses type: "foo" and kind: "bar" as discriminants. In Rust these map to #[serde(tag = "type")] and #[serde(tag = "kind")] tagged enums.
• Forward compatibility. The daemon's design explicitly says "frontends ignore unknown kinds". We mirror that by using #[serde(other)] on a trailing Unknown variant and #[serde(flatten)] on extensible metadata maps. Adding new server-side message kinds never breaks an old Rust client — they deserialize into [DaemonMessage::Unknown] and the TUI logs + skips them.
• Tool state as full replacement. [ToolState] is a tagged enum where each phase carries its own shape. When a [SessionMessageDelta] arrives with tool_state_update, replace the whole [ToolInfo::state] — do not merge fields.

Versioning

[PROTOCOL_VERSION] is compared against the protocol_version field the daemon sends on auth.ok. Mismatch is non-fatal (the daemon's additive changes keep old clients working), but the client warns the user so they can upgrade.