feat: implement AdminRoute for admin access control and enhance UsersPage with user management features

src/App.tsx

@@ -27,6 +27,24 @@ function ProtectedRoute({ children }: { children: React.ReactNode }) {
   return <>{children}</>
 }
 
+function AdminRoute({ children }: { children: React.ReactNode }) {
+  const { user, loading } = useAuth()
+  
+  if (loading) {
+    return <div className="min-h-screen flex items-center justify-center">Loading...</div>
+  }
+  
+  if (!user) {
+    return <Navigate to="/login" replace />
+  }
+  
+  if (user.role !== 'admin') {
+    return <Navigate to="/" replace />
+  }
+  
+  return <>{children}</>
+}
+
 function AppRoutes() {
   const { user } = useAuth()
   
@@ -56,14 +74,14 @@ function AppRoutes() {
         </ProtectedRoute>
       } />
       <Route path="/admin/users" element={
-        <ProtectedRoute>
+        <AdminRoute>
           <UsersPage />
-        </ProtectedRoute>
+        </AdminRoute>
       } />
       <Route path="/admin/settings" element={
-        <ProtectedRoute>
+        <AdminRoute>
           <SettingsPage />
-        </ProtectedRoute>
+        </AdminRoute>
       } />
     </Routes>
   )