fix(ui-react): cap namespace selector list height to prevent overflow

[luizhf42]

What

The namespace selector dropdown now caps its namespace list at a fixed height and scrolls internally instead of growing unbounded.

Why

With a large number of namespaces, the list grew taller than the viewport, pushing the dropdown past the body height and breaking the page layout.

Changes

• NamespaceSelector: added max-h-72 overflow-y-auto to the namespace list container so only the list scrolls while the active-namespace header and the Create/Admin footers stay pinned. This matches the existing scroll pattern used by InvitationsMenu (max-h-[360px] overflow-y-auto) and PendingDevices (max-h-[280px] overflow-y-auto).

Testing

Open the selector in an account with enough namespaces to exceed ~5 rows and confirm the list scrolls within the dropdown, the header and footer stay fixed, and the dropdown no longer overflows the viewport.

[github-actions]

Claude finished @luizhf42's task in 1m 43s —— View job

---

Code Review Complete

Reviewed 1 file across code quality, security, testing, language patterns, and architecture — no issues found. The code looks good as-is.

The change correctly applies overflow-y-auto max-h-72 to the namespace list container, consistent with the existing scroll patterns in InvitationsMenu (max-h-[360px] overflow-y-auto) and PendingDevices (max-h-[280px] overflow-y-auto). The footer actions (Admin Console link, Create namespace) remain outside the scrollable area as intended.

---

If you push additional changes and want a new review, tag @shellhub-io/admin and a team member can trigger it.