Segment-restricted navigation for the new portal & widget (native page/section gating by user segment)

Description: Add native controls to show/hide navigation items and pages (e.g. Roadmap, Suggestions/Feedback, Changelog) in the new portal and new widget, based on the logged-in user's segment — without any custom JavaScript. Problem: Today, restricting portal/widget sections by segment requires custom JS. For example, Dendreo only wants paid customers to access the roadmap and suggestions, while all customers can see the changelog. They currently do this with a custom snippet that reads the user's segment (widgetusersegment) and hides/redirects based on whether the user is in a full-access segment. With the portal and widget redesign, this custom code is fragile and may need to be reworked at migration — and segment-based page/navigation gating isn't available natively (only category-level segmentation exists today). Benefit: No custom code to maintain — survives redesigns and migrations. Fine-grained, per-segment control over who sees Roadmap / Suggestions / Changelog. Consistent behaviour across the new portal and the new widget.