fix(webui): broadcast runtime model updates

Co-authored-by: Cursor <cursoragent@cursor.com>

webui/src/tests/useNanobotStream.test.tsx

@@ -134,28 +134,6 @@ describe("useNanobotStream", () => {
     ]);
   });
 
-  it("reports runtime model name updates from message frames", () => {
-    const fake = fakeClient();
-    const onModelNameChange = vi.fn();
-    renderHook(
-      () => useNanobotStream("chat-model", EMPTY_MESSAGES, false, undefined, onModelNameChange),
-      {
-        wrapper: wrap(fake.client),
-      },
-    );
-
-    act(() => {
-      fake.emit("chat-model", {
-        event: "message",
-        chat_id: "chat-model",
-        text: "Switched model preset to `fast`.",
-        model_name: "openai/gpt-4.1",
-      });
-    });
-
-    expect(onModelNameChange).toHaveBeenCalledWith("openai/gpt-4.1");
-  });
-
   it("suppresses redundant stream confirmation after assistant media", () => {
     const fake = fakeClient();
     const { result } = renderHook(() => useNanobotStream("chat-img-result", EMPTY_MESSAGES), {