feat: PWA overhaul

- Remove debug artifact from login page ('Use Link component: HOME')
- Full icon set: 48/72/96/128/144/152/192/384/512 + maskable variants
- Proper manifest: display_override, shortcuts, categories, scope
- Better service worker: offline fallback page, pre-caching, stale-while-revalidate
- Custom install banner (Android beforeinstallprompt + iOS instructions)
- Connection status indicator (online/offline toast)
- Updated index.html with proper favicon sizes and meta tags

web/src/App.tsx

@@ -12,6 +12,8 @@ import { DMChat } from './components/DMChat.tsx';
 import { ForgotPasswordPage } from './components/ForgotPasswordPage.tsx';
 import { ResetPasswordPage } from './components/ResetPasswordPage.tsx';
 import { useAuthStore } from './stores/auth.ts';
+import { InstallBanner } from './components/InstallBanner.tsx';
+import { ConnectionStatus } from './components/ConnectionStatus.tsx';
 
 function ProtectedRoute({ children }: { children: React.ReactNode }) {
   const isAuthenticated = useAuthStore((state) => state.isAuthenticated);
@@ -32,6 +34,8 @@ function App() {
 
   return (
     <BrowserRouter>
+      <ConnectionStatus />
+      <InstallBanner />
       <Routes>
         <Route path="/login" element={<LoginForm />} />
         <Route path="/forgot-password" element={<ForgotPasswordPage />} />