removeProvider method
Removes a saved custom provider from the registry (the /provider
picker's Delete action). Clears the active-entry marker when needed and
notifies AgentCliConfig.onProviderChanged so the host persists the
registry — deletion never switches the active model, so without the
notification the deletion silently vanished on restart.
Implementation
Future<void> removeProvider(CustomProviderEntry entry) async {
final registry = config.customProviders;
if (registry == null) return;
registry.entries.removeWhere((e) => e.name == entry.name);
if (_activeCustomName == entry.name) _activeCustomName = null;
io.writeln('deleted provider ${entry.name}');
await config.onProviderChanged?.call(_providerKind, _apiKey);
}