A ⌘K palette with no visible entry point is itself a discoverability +
a11y gap (keyboard/SR users can't find it). Added a labeled 'Jump to…'
button (aria-label spells out the shortcut) that dispatches a
'commandpalette:open' event the palette now also listens for. Verified
the other top a11y items are already satisfied here (sonner Toaster
provides the aria-live region; sidebar icon buttons are aria-labeled;
skip-link + drawer focus mgmt already present).
New CommandPalette over the existing unused cmdk primitive, mounted in
the (app) layout. Grouped nav destinations mirroring the sidebar; admin/
manage entries gated by the same isAdmin + navPerms the layout already
resolves (so it never offers a route the guard would bounce). Opens on
Cmd/Ctrl-K, type-to-filter, Enter to jump.