Wire-protocol encoder/decoder for vibesurfer.

vs-protocol is the shared specification of the line-oriented wire format documented in docs/PROTOCOL.md at the workspace root. The daemon and the CLI both link this crate; the daemon emits, the CLI parses (and vice-versa for requests).

Layout

• [codes] — short codes ([Role], [Op], [ErrorCode], [WarningCode]) with Display and FromStr implementations.
• [tree] — in-memory [Tree] / [Node] / [Ref] and the indented full-tree wire format.
• [delta] — [DeltaOp] with encode/parse/[apply]/[diff].
• [envelope] — [StateToken], [Warning], [Envelope], and [ResponseHead].
• [request] — [Request] line.
• [error::ParseError] — every fallible parser returns this.