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>

artifacthub-repo.yml

@@ -1,4 +1,4 @@
-repositoryID: fb4c3789-de2b-4667-8fff-34f22e5648da
+repositoryID: fc3397f6-a75a-4950-ab50-da75c08a8089
 owners:
   - name: cpfarhood
     email: "chris@farhood.org"