Function pty_connect

crates/opencode-server/src/routes.rs:3463–3486

WebSocket endpoint that bridges a client to a PTY session, matching the TS `Pty.connect` protocol: 1. On connect: replay buffered output from the requested cursor, then send a binary metadata frame (`0x00` + JSON `{"cursor": }`) so the client knows the current position. 2. Forward live PTY output to the client as binary frames. 3. Forward text/binary messages from the client into the PTY as inpu

(
    Path(id): Path<String>,
    Query(query): Query<PtyConnectQuery>,
    ws: WebSocketUpgrade,
)

///   2. Forward live PTY output to the client as binary frames.
///   3. Forward text/binary messages from the client into the PTY as input.
async fn pty_connect(
    Path(id): Path<String>,
    Query(query): Query<PtyConnectQuery>,
    ws: WebSocketUpgrade,
) -> impl IntoResponse {
    let manager = get_pty_manager();

    // Validate the session exists before upgrading.
    let subscription = match manager.subscribe(&id).await {
        Ok(sub) => sub,
        Err(_) => {
            return axum::response::Response::builder()
                .status(404)
                .body(axum::body::Body::from("PTY session not found"))
                .unwrap()
                .into_response();
        }
    };

    let cursor_param = query.cursor.unwrap_or(0);

    ws.on_upgrade(move |socket| handle_pty_websocket(socket, subscription, cursor_param))
        .into_response()
}

async fn handle_pty_websocket(mut socket: WebSocket, sub: PtySubscription, cursor_param: i64) {
    // --- Phase 1: Replay buffered output ---