feat(ui): render the Cockpit utility launchers and compact Radio controls from a store

The Display and Radio launchers, their popovers and the compact Radio
transport, Enable button and volume now render from the Radio store.
RadioControls owns the disclosure state; Cockpit Escape and the Display
reveal read that state instead of the DOM, and the Enable toggle guards
re-presses synchronously. The compact transport reuses the panel's
transport state and adds only its glyph and title.

src/ui/cockpitInput.js

@@ -8,10 +8,8 @@ export function onKeyDown(event) {
     // focus. Its target handler closes the overlay and restores attribution
     // focus; Cockpit must stay active behind it.
     if (event.target?.closest?.('.cesium-credit-lightbox')) return;
-    if (
-      document.querySelector('#cockpit-utility-controls [aria-expanded="true"]')
-    )
-      return;
+    // An open Display or Radio popover takes Escape itself.
+    if (this.isUtilityDisclosureOpen?.()) return;
     if (this.context?.contains(event.target) && !this.contextCollapsed) {
       event.preventDefault();
       event.stopImmediatePropagation();