Include Aurora nav section in the sidebar's single-open accordion (v2.3.1)

Aurora's branded nav section had its own independent expand/collapse
state, so it stayed open regardless of which native menu section was
expanded — the one exception to the single-open accordion. Unified
under one openId ref (a sentinel value for Aurora alongside real
native-menu item ids) so expanding either collapses the other.

Co-Authored-By: Claude Sonnet 5 <[email protected]>

app/package.json

@@ -1,6 +1,6 @@
 {
   "name": "aurora-admin-app",
-  "version": "2.3.0",
+  "version": "2.3.1",
   "private": true,
   "type": "module",
   "scripts": {