fix: add labels to container API, null-safe ContainerGroup, error boundary

- containers/route.ts: include c.Labels in response (was missing, caused null crash)
- ContainerGroup.tsx: null-safe getTraefikUrl with optional chaining
- error.tsx: add Next.js error boundary for graceful client-side error handling

src/app/api/containers/route.ts

@@ -47,6 +47,7 @@ export async function GET() {
           state: c.State,
           status: c.Status,
           ports: c.Ports || [],
+          labels: c.Labels || {},
           cpu,
           memory,
           stats: statsText,

src/app/error.tsx

@@ -0,0 +1,30 @@
+"use client";
+
+import { useEffect } from "react";
+
+export default function Error({
+  error,
+  reset,
+}: {
+  error: Error & { digest?: string };
+  reset: () => void;
+}) {
+  useEffect(() => {
+    console.error("Dashboard error:", error);
+  }, [error]);
+
+  return (
+    <div className="min-h-screen bg-gray-900 flex items-center justify-center">
+      <div className="bg-gray-800 rounded-lg border border-gray-700 p-8 max-w-md text-center">
+        <h2 className="text-xl font-bold text-white mb-4">Something went wrong</h2>
+        <p className="text-gray-400 mb-6 text-sm">{error.message}</p>
+        <button
+          onClick={reset}
+          className="px-4 py-2 bg-blue-600 hover:bg-blue-700 text-white rounded-lg text-sm transition-colors"
+        >
+          Try again
+        </button>
+      </div>
+    </div>
+  );
+}

src/components/ContainerGroup.tsx

@@ -28,7 +28,8 @@ export default function ContainerGroup({
     }
   };
 
-  const getTraefikUrl = (labels: Record<string, string>) => {
+  const getTraefikUrl = (labels?: Record<string, string> | null) => {
+    if (!labels || typeof labels !== "object") return null;
     for (const key of Object.keys(labels)) {
       if (key.includes("traefik.http.routers") && key.endsWith(".rule")) {
         const match = labels[key].match(/Host\(`([^`]+)`\)/);
@@ -96,7 +97,7 @@ export default function ContainerGroup({
                   <span className="text-gray-300">{container.status}</span>
                 </div>
 
-                {container.ports.length > 0 && (
+                {container.ports && container.ports.length > 0 && (
                   <div className="flex items-center justify-between text-xs">
                     <span className="text-gray-400">Ports</span>
                     <span className="text-gray-300">