feat: add 404 not found page

app/routes/not-found.tsx

@@ -0,0 +1,33 @@
+import { Link } from 'react-router';
+import { Button } from '~/components/ui/button';
+import { Card } from '~/components/ui/card';
+import { Badge } from '~/components/ui/badge';
+import { FileQuestion } from 'lucide-react';
+
+export default function NotFound() {
+    return (
+        <div className="relative min-h-screen bg-[#0D0D0D] flex items-center justify-center p-6 overflow-hidden select-none font-sans text-white">
+            <div className="absolute top-[30%] left-[30%] w-[40%] h-[40%] rounded-full bg-orange-500/5 blur-[130px] pointer-events-none" />
+
+            <Card className="p-6 text-center border-neutral-850 shadow-2xl relative z-10 space-y-4 max-w-xs">
+                <div className="inline-flex w-12 h-12 bg-neutral-900 border border-neutral-850 rounded-xl items-center justify-center shadow-md mb-2">
+                    <FileQuestion className="text-orange-500" size={22} />
+                </div>
+                <div className="space-y-1">
+                    <Badge variant="orange">404 Error</Badge>
+                    <h1 className="text-lg font-bold text-white uppercase tracking-tight mt-2">Page Not Found</h1>
+                </div>
+                <p className="text-neutral-500 text-[11px] leading-relaxed max-w-[240px] mx-auto">
+                    The page you are looking for does not exist or has been moved.
+                </p>
+                <div className="pt-3">
+                    <Link to="/" className="block w-full">
+                        <Button size="sm" className="w-full font-bold uppercase tracking-wider text-[10px] py-4 h-10">
+                            Return to Dashboard
+                        </Button>
+                    </Link>
+                </div>
+            </Card>
+        </div>
+    );
+}