Add loading.js and error.js for all routes, secure admin page with 404

- Added loading.js (dark/light variants) for all 14 routes
- Added error.js (dark/light variants) for all 14 routes
- Added global not-found.js and loading.js at root
- Admin page shows 404 illustration for non-admin users instead of redirecting

app/admin/page.js

@@ -2,15 +2,16 @@
 
 import { motion } from 'framer-motion';
 import { useState, useEffect } from 'react';
-import { useRouter } from 'next/navigation';
 import { useTranslation } from 'react-i18next';
+import Link from 'next/link';
 import { 
   Home, 
   Calendar, 
   Users,
   DollarSign,
   TrendingUp,
-  Bell
+  Bell,
+  Frown
 } from 'lucide-react';
 import DashboardStats from '../components/admin/DashboardStats';
 import PropertiesTable from '../components/admin/PropertiesTable';
@@ -24,16 +25,57 @@ import '../i18n/config';
 
 export default function AdminPage() {
   const { t, i18n } = useTranslation();
-  const router = useRouter();
   const [activeTab, setActiveTab] = useState('dashboard');
   const [showAddProperty, setShowAddProperty] = useState(false);
   const [notifications, setNotifications] = useState(3);
+  const [isAdmin, setIsAdmin] = useState(false);
+  const [checked, setChecked] = useState(false);
 
   useEffect(() => {
-    if (!AuthService.isAuthenticated() || !AuthService.isAdmin()) {
-      router.push('/');
-    }
-  }, [router]);
+    setIsAdmin(AuthService.isAuthenticated() && AuthService.isAdmin());
+    setChecked(true);
+  }, []);
+
+  // ─── 404 for non-admins ───
+  if (checked && !isAdmin) {
+    return (
+      <div className="min-h-screen bg-gray-50 flex items-center justify-center p-4">
+        <motion.div
+          initial={{ opacity: 0, y: 20 }}
+          animate={{ opacity: 1, y: 0 }}
+          className="text-center max-w-md"
+        >
+          <div className="mb-6">
+            <svg viewBox="0 0 200 180" className="w-72 h-52 mx-auto">
+              <circle cx="100" cy="70" r="60" fill="#fef3c7" />
+              <circle cx="80" cy="60" r="8" fill="#92400e" />
+              <circle cx="120" cy="60" r="8" fill="#92400e" />
+              <path d="M80 85 Q100 75 120 85" stroke="#92400e" strokeWidth="3" fill="none" strokeLinecap="round" />
+              <text x="100" y="140" textAnchor="middle" fontSize="16" fontWeight="bold" fill="#6b7280">عذراً!</text>
+              <text x="100" y="160" textAnchor="middle" fontSize="12" fill="#9ca3af">الصفحة غير موجودة</text>
+            </svg>
+          </div>
+          <h2 className="text-2xl font-bold text-gray-900 mb-2">404 - الصفحة غير موجودة</h2>
+          <p className="text-gray-500 mb-8">عذراً، لا يمكنك الوصول إلى هذه الصفحة</p>
+          <Link
+            href="/"
+            className="inline-flex items-center gap-2 bg-amber-500 text-white px-6 py-3 rounded-xl font-medium hover:bg-amber-600 transition-colors"
+          >
+            <Home className="w-5 h-5" />
+            العودة للرئيسية
+          </Link>
+        </motion.div>
+      </div>
+    );
+  }
+
+  if (!checked) {
+    return (
+      <div className="min-h-screen bg-gray-50 flex items-center justify-center">
+        <div className="w-14 h-14 border-4 border-amber-500 border-t-transparent rounded-full animate-spin" />
+      </div>
+    );
+  }
 
   const tabs = [
     { id: 'dashboard', label: 'لوحة التحكم', icon: Home },