delete the toaster that could never show a toast, and title the system settings page

`ui/toaster.tsx` was mounted in frontend.tsx and rendered a permanently empty
list: nothing anywhere imports `useToast`/`toast` from `ui/use-toast.ts`. The
app's real toaster is sonner, which is mounted beside it and has four callers.

`@radix-ui/react-toast` stays declared in the two package.json files on
purpose — installs are frozen, and dropping it means a deliberate
`bun install --no-frozen-lockfile` and a read of the lockfile diff.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src/apps/officer-web/frontend.tsx

@@ -6,12 +6,10 @@ import { seedAppRegistry, seedWidgetRegistry } from 'officerdev';
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
 import { ColorModeProvider } from '@/components/ui/ThemeProvider';
 import { I18nBridge } from '@/lib/I18nBridge';
-import { Toaster } from '@/components/ui/toaster';
 import { Toaster as Sonner } from 'sonner';
 import { TooltipProvider } from '@/components/ui/tooltip';
 import './styles/index.css';
 
-
 const queryClient = new QueryClient({
   defaultOptions: {
     queries: {
@@ -32,7 +30,6 @@ const app = (
       <ColorModeProvider>
         <I18nBridge>
           <TooltipProvider>
-            <Toaster />
             <Sonner position="top-center" toastOptions={{ style: { padding: '16px 20px', fontSize: '16px' } }} />
             <App />
           </TooltipProvider>

src/apps/officer-web/state/usePageTitle.ts

@@ -11,6 +11,7 @@ const RULES: TitleRule[] = [
   { match: (p) => p.startsWith('/settings/profile'), title: 'Profile' },
   { match: (p) => p.startsWith('/settings/integrations'), title: 'Integrations' },
   { match: (p) => p.startsWith('/settings/user-management'), title: 'User Management' },
+  { match: (p) => p.startsWith('/settings/system'), title: 'System' },
   { match: (p) => p.startsWith('/settings'), title: 'Settings' },
   { match: (p) => p.startsWith('/chat'), title: 'Chat' },
   { match: (p) => p.startsWith('/email'), title: 'Email' },