fix: remove reviewer response success toast

frontend/src/shell/WidgetHost.response.test.tsx

@@ -7,7 +7,7 @@ import { WidgetHost } from "./WidgetHost";
 
 beforeEach(() => useSessionStore.getState().resetSession());
 
-test("a gate choice shows progress, prevents duplicate clicks, and confirms delivery", async () => {
+test("a gate choice shows progress, prevents duplicate clicks, and stays silent on success", async () => {
   let release!: () => void;
   const held = new Promise<void>((resolve) => { release = resolve; });
   let requests = 0;
@@ -36,10 +36,7 @@ test("a gate choice shows progress, prevents duplicate clicks, and confirms deli
 
   act(() => release());
   await waitFor(() => expect(useSessionStore.getState().pendingWidget).toBeNull());
-  expect(useSessionStore.getState().toasts.at(-1)).toEqual({
-    level: "success",
-    text: "Response sent. The model is continuing.",
-  });
+  expect(useSessionStore.getState().toasts).toEqual([]);
 
   act(() => useSessionStore.setState({
     pendingWidget: {