fix(ipc): Propagate per-client disconnects, add proper routing for targeted messages, and remove unused node-ipc deps

ts/classes.transports.ts

@@ -267,7 +267,8 @@ export class UnixSocketTransport extends IpcTransport {
             this.clientIdToSocket.delete(clientId);
           }
           this.socketToClientId.delete(socket);
-          this.emit('clientDisconnected', socket);
+          // Emit with clientId if known so higher layers can react
+          this.emit('clientDisconnected', socket, clientId);
         });
 
         socket.on('drain', () => {