feat: Add authentication system and admin panel

- Add User model with authentication
- Create JWT-based auth service
- Add login page with admin/admin default credentials
- Create admin panel with user management, settings, and site configuration
- Move settings to admin section (admin only)
- Change search page from multi-site checkboxes to single site selector
- Add logout functionality to layout
- Protect routes with authentication

frontend/src/App.jsx

@@ -1,25 +1,104 @@
 import React from 'react'
-import { BrowserRouter as Router, Routes, Route } from 'react-router-dom'
+import { BrowserRouter as Router, Routes, Route, Navigate } from 'react-router-dom'
 import { Toaster } from 'sonner'
 import Layout from '@/components/layout/Layout'
 import Dashboard from '@/pages/Dashboard'
 import Search from '@/pages/Search'
-import Settings from '@/pages/Settings'
+import Login from '@/pages/Login'
+import Admin from '@/pages/Admin'
 import { useTheme } from '@/hooks/use-theme'
+import { AuthProvider, useAuth } from '@/hooks/use-auth'
 
-export default function App() {
+// Protected route wrapper
+function ProtectedRoute({ children, adminOnly = false }) {
+    const { isAuthenticated, isAdmin, loading } = useAuth();
+
+    if (loading) {
+        return (
+            <div className="min-h-screen flex items-center justify-center">
+                <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary"></div>
+            </div>
+        );
+    }
+
+    if (!isAuthenticated) {
+        return <Navigate to="/login" replace />;
+    }
+
+    if (adminOnly && !isAdmin) {
+        return <Navigate to="/" replace />;
+    }
+
+    return children;
+}
+
+// Public route that redirects to home if already logged in
+function PublicRoute({ children }) {
+    const { isAuthenticated, loading } = useAuth();
+
+    if (loading) {
+        return (
+            <div className="min-h-screen flex items-center justify-center">
+                <div className="animate-spin rounded-full h-8 w-8 border-b-2 border-primary"></div>
+            </div>
+        );
+    }
+
+    if (isAuthenticated) {
+        return <Navigate to="/" replace />;
+    }
+
+    return children;
+}
+
+function AppRoutes() {
     const { theme, toggleTheme } = useTheme();
+    const { isAuthenticated } = useAuth();
 
     return (
-        <Router>
+        <>
             <Toaster position="bottom-right" theme={theme} />
-            <Layout theme={theme} toggleTheme={toggleTheme}>
-                <Routes>
-                    <Route path="/" element={<Dashboard />} />
-                    <Route path="/search" element={<Search />} />
-                    <Route path="/settings" element={<Settings />} />
-                </Routes>
-            </Layout>
+            <Routes>
+                <Route
+                    path="/login"
+                    element={
+                        <PublicRoute>
+                            <Login />
+                        </PublicRoute>
+                    }
+                />
+                <Route
+                    path="/*"
+                    element={
+                        <ProtectedRoute>
+                            <Layout theme={theme} toggleTheme={toggleTheme}>
+                                <Routes>
+                                    <Route path="/" element={<Dashboard />} />
+                                    <Route path="/search" element={<Search />} />
+                                    <Route
+                                        path="/admin"
+                                        element={
+                                            <ProtectedRoute adminOnly>
+                                                <Admin />
+                                            </ProtectedRoute>
+                                        }
+                                    />
+                                </Routes>
+                            </Layout>
+                        </ProtectedRoute>
+                    }
+                />
+            </Routes>
+        </>
+    );
+}
+
+export default function App() {
+    return (
+        <Router>
+            <AuthProvider>
+                <AppRoutes />
+            </AuthProvider>
         </Router>
     );
 }