Function connect_picker_sources 

pub async fn connect_picker_sources(
    client: PickerClient,
) -> Result<Vec<Arc<dyn PickerSourceGenerator>>, PluginHostError>

Convenience: drive registration and wrap each declared source as the Arc<dyn PickerSourceGenerator> the PickerRegistry stores.

Registration itself is one call per source — registry.register_generator(source) — keyed by its spec().id; provenance (SourceLayer::Plugin) is a grammar-contribution concern (PH7.7), not a picker-registry one. Returns a Vec since OR.5b: one component may declare several, which is the whole point of that slice.