feat(ui): add RuntimePage and DashboardPage tab wrappers

Thin wrapper pages that conditionally render AgentHealth/AgentInstance
and RoutesMetrics/RouteDetail based on URL params for the nav redesign.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/src/pages/DashboardTab/DashboardPage.tsx

@@ -0,0 +1,17 @@
+import { useParams } from 'react-router';
+import { lazy, Suspense } from 'react';
+import { Spinner } from '@cameleer/design-system';
+
+const RoutesMetrics = lazy(() => import('../Routes/RoutesMetrics'));
+const RouteDetail = lazy(() => import('../Routes/RouteDetail'));
+
+const Fallback = <div style={{ display: 'flex', justifyContent: 'center', padding: '4rem' }}><Spinner size="lg" /></div>;
+
+export default function DashboardPage() {
+  const { routeId } = useParams<{ appId?: string; routeId?: string }>();
+
+  if (routeId) {
+    return <Suspense fallback={Fallback}><RouteDetail /></Suspense>;
+  }
+  return <Suspense fallback={Fallback}><RoutesMetrics /></Suspense>;
+}