Element: #241 The skeleton prop (feedback/skeleton)
What it shows: Avatar, KpiCard, TextField and Card all switched to their skeleton state by one shared loading flag.
When to use: Loading states where real components keep their exact size and show a placeholder until data arrives.
Spec:
- `let loading = $state(true)` passed as `skeleton={loading}` to four components
- `` and ``
- ``
- `` with one paragraph of content
- Toggle `