feat: add per-namespace detail pages with dynamic sidebar sub-items

Add drill-down namespace views under the Polaris sidebar entry. Each
namespace gets a sidebar sub-item registered dynamically from audit data,
linking to /polaris/:namespace with a score summary and per-resource table.

Introduces a shared PolarisDataContext so the sidebar registrar and view
components share a single data fetch. Also updates the Artifact Hub
repository ID.

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

src/components/DynamicSidebarRegistrar.tsx

@@ -0,0 +1,29 @@
+import { registerSidebarEntry } from '@kinvolk/headlamp-plugin/lib';
+import React from 'react';
+import { usePolarisDataContext } from '../api/PolarisDataContext';
+import { getNamespaces } from '../api/polaris';
+
+const registeredNamespaces = new Set<string>();
+
+export default function DynamicSidebarRegistrar() {
+  const { data } = usePolarisDataContext();
+
+  React.useEffect(() => {
+    if (!data) return;
+
+    const namespaces = getNamespaces(data);
+    for (const ns of namespaces) {
+      if (registeredNamespaces.has(ns)) continue;
+      registeredNamespaces.add(ns);
+      registerSidebarEntry({
+        parent: 'polaris',
+        name: `polaris-ns-${ns}`,
+        label: ns,
+        url: `/polaris/${ns}`,
+        icon: 'mdi:folder-outline',
+      });
+    }
+  }, [data]);
+
+  return null;
+}