cachedPanel method
The cached panel, if there is a usable one — parsed, never rendered from bytes this build cannot read. Touches storage only, never the network.
Implementation
Future<PanelSchema?> cachedPanel() async {
final cache = _cache;
final key = _effectiveKey;
if (cache == null || key == null) return null;
return (await _readValid(cache, key))?.panel;
}