fix(gateway): report unsupported node events (#123719)

Closes #123717

src/gateway/server-node-events.ts

@@ -1221,7 +1221,7 @@ export const handleNodeEvent = async (
       }
     }
     default:
-      return undefined;
+      return { ok: true, event: evt.event, handled: false, reason: "unsupported_event" };
   }
 };
 /* oxlint-disable max-lines -- TODO: split this grandfathered oversized file. */

src/gateway/server.roles-allowlist-update.test.ts

@@ -364,13 +364,26 @@ describe("gateway role enforcement", () => {
       expect(invokeRes.ok).toBe(false);
       expect(invokeRes.error?.message ?? "").toContain("unauthorized role");
 
-      nodeClient = await connectNodeClientWithPairing({
+      nodeClient = await connectNodeClientWithNodePairing({
         port,
         commands: [],
         instanceId: "node-role-enforcement",
         displayName: "node-role-enforcement",
       });
 
+      const unsupportedEvent = await nodeClient.request<{
+        ok: boolean;
+        event?: string;
+        handled?: boolean;
+        reason?: string;
+      }>("node.event", { event: "test.unsupported", payload: { ok: true } });
+      expect(unsupportedEvent).toEqual({
+        ok: true,
+        event: "test.unsupported",
+        handled: false,
+        reason: "unsupported_event",
+      });
+
       const binsPayload = await nodeClient.request("skills.bins", {});
       expect(Array.isArray(binsPayload?.bins)).toBe(true);