New ArborXR portal layout

We rebuilt the navigation in the ArborXR portal. Everything now lives in a single sidebar instead of a mix of top tabs and sub tabs, so pages like the content library take one click instead of three. It also gives us room to add new product areas without crowding the top of the screen.

It's opt in. You'll see a prompt in the portal to switch, and you can switch back to the classic layout at any time. The setting applies to your user account only, so trying it does not change anything for your teammates.

On November 16th, the new layout becomes the default for everyone and the classic layout goes away. That gives you six weeks to move at your own pace and update any internal runbooks or training that reference the old navigation.