feat(gateway): add node capability negotiation foundation

src/gateway/router.ts

@@ -14,6 +14,9 @@ export class Router {
   }
 
   async dispatch(request: GatewayRequest, send: SendFn): Promise<OutboundMessage | void> {
+    if (request.method.startsWith('node.') && !request.params) {
+      return makeError(request.id, ErrorCode.InvalidRequest, 'params are required for node methods');
+    }
     const handler = this.handlers.get(request.method);
     if (!handler) {
       return makeError(request.id, ErrorCode.MethodNotFound, `Unknown method: ${request.method}`);