Fix ESLint errors: Add missing imports and remove unused variables

frontend/src/components/Layout.js

@@ -12,7 +12,7 @@ import {
 } from '@heroicons/react/24/outline';
 
 const Layout = () => {
-  const { user, logout, isSuperAdmin, isTrainer, isTrainee } = useAuth();
+  const { user, logout, isSuperAdmin } = useAuth();
   const navigate = useNavigate();
   const location = useLocation();
   const [sidebarOpen, setSidebarOpen] = useState(false);

frontend/src/pages/CourseDetail.js

@@ -8,9 +8,7 @@ import {
   ClockIcon,
   UserIcon,
   StarIcon,
-  CurrencyDollarIcon,
   BookOpenIcon,
-  CheckCircleIcon,
 } from '@heroicons/react/24/outline';
 import LoadingSpinner from '../components/LoadingSpinner';
 import toast from 'react-hot-toast';

frontend/src/pages/Courses.js

@@ -5,16 +5,16 @@ import { useAuth } from '../contexts/AuthContext';
 import { coursesAPI } from '../services/api';
 import {
   MagnifyingGlassIcon,
-  FunnelIcon,
   PlusIcon,
   StarIcon,
   ClockIcon,
   UserIcon,
+  AcademicCapIcon,
 } from '@heroicons/react/24/outline';
 import LoadingSpinner from '../components/LoadingSpinner';
 
 const Courses = () => {
-  const { user, isTrainer, isSuperAdmin } = useAuth();
+  const { isTrainer, isSuperAdmin } = useAuth();
   const [search, setSearch] = useState('');
   const [category, setCategory] = useState('');
   const [level, setLevel] = useState('');

frontend/src/pages/Dashboard.js

@@ -6,7 +6,6 @@ import {
   AcademicCapIcon,
   UsersIcon,
   ClockIcon,
-  CurrencyDollarIcon,
   ChartBarIcon,
   UserGroupIcon,
   BookOpenIcon,

frontend/src/pages/Users.js

@@ -6,7 +6,6 @@ import {
   PencilIcon,
   TrashIcon,
   MagnifyingGlassIcon,
-  FunnelIcon,
 } from '@heroicons/react/24/outline';
 import LoadingSpinner from '../components/LoadingSpinner';
 import toast from 'react-hot-toast';