Add /kiosk shell (login, app home, iframe launcher) and Kiosk admin tab

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

src/App.tsx

@@ -2,6 +2,7 @@ import { BrowserRouter, Routes, Route, Navigate, useParams } from 'react-router-
 import { AuthGate } from './components/AuthGate'
 import { Login } from './pages/Login'
 import { Register } from './pages/Register'
+import { Kiosk } from './pages/Kiosk'
 import { Dashboard } from './pages/Dashboard'
 import { AppFrame } from './pages/AppFrame'
 import { AdminUsers } from './pages/AdminUsers'
@@ -48,6 +49,7 @@ export default function App() {
       <Routes>
         <Route path="/login"    element={<Login />} />
         <Route path="/register" element={<Register />} />
+        <Route path="/kiosk"    element={<Kiosk />} />
         <Route path="/*" element={
           <AuthGate>
             {user => (