🐛(frontend) use state instead of a ref for MoreControls container

After the recent refactoring, `MoreControls` only renders once. On
that first render, the container ref is `null`, and when it later
gets a reference to the div, the ref update does not trigger a
re-render.

As a result, the additional controls were never showing up.

Switch from a ref to a state to track the container element. State
updates do trigger a re-render, so the controls now show as
expected once the container is available.

CHANGELOG.md

@@ -22,6 +22,7 @@ and this project adheres to
 - ⬆️(backend) bump sqlparse from 0.5.5 to 0.6.0
 - ⬆️(mail) bump @html-to/text-cli from 0.6.0 to 0.6.1
 - 🐛(frontend) treat client-initiated connect aborts as events
+- 🐛(frontend) use state instead of a ref for MoreControls container
 
 ## [1.27.0] - 2026-08-14