feat(web): add toast notifications for settings save status

web/src/App.tsx

@@ -5,9 +5,12 @@ import { Activity } from "./pages/Activity";
 import { Settings } from "./pages/Settings";
 import "./index.css";
 
+import { Toaster } from "sonner";
+
 export function App() {
   return (
     <BrowserRouter>
+      <Toaster richColors position="top-right" theme="dark" />
       <Routes>
         <Route path="/" element={<DashboardLayout />}>
           <Route index element={<Dashboard />} />