feat: add admin pages for plans, users, and placeholders

- AdminPlans: full CRUD UI with cards, visibility toggle
- AdminUsers: search, suspend/unsuspend, grant Pro access
- AdminPaymentMethods: placeholder
- AdminPayments: placeholder
- AdminSettings: placeholder
- All routes wired in App.tsx
- Admin panel fully navigable

apps/web/src/App.tsx

@@ -8,6 +8,11 @@ import { OtpVerification } from './components/pages/OtpVerification'
 import { AuthCallback } from './components/pages/AuthCallback'
 import { AdminLayout } from './components/admin/AdminLayout'
 import { AdminDashboard } from './components/admin/pages/AdminDashboard'
+import { AdminPlans } from './components/admin/pages/AdminPlans'
+import { AdminPaymentMethods } from './components/admin/pages/AdminPaymentMethods'
+import { AdminPayments } from './components/admin/pages/AdminPayments'
+import { AdminUsers } from './components/admin/pages/AdminUsers'
+import { AdminSettings } from './components/admin/pages/AdminSettings'
 import { Loader2 } from 'lucide-react'
 
 function ProtectedRoute({ children }: { children: React.ReactNode }) {
@@ -64,6 +69,11 @@ export default function App() {
             {/* Admin Routes */}
             <Route path="/admin" element={<ProtectedRoute><AdminLayout /></ProtectedRoute>}>
               <Route index element={<AdminDashboard />} />
+              <Route path="plans" element={<AdminPlans />} />
+              <Route path="payment-methods" element={<AdminPaymentMethods />} />
+              <Route path="payments" element={<AdminPayments />} />
+              <Route path="users" element={<AdminUsers />} />
+              <Route path="settings" element={<AdminSettings />} />
             </Route>
 
             {/* Protected Routes */}