Function emit_layout_for_tab 

async fn emit_layout_for_tab(
    wstore: &Arc<WaveStore>,
    event_bus: &Arc<EventBus>,
    tab_id: String,
    context: &'static str,
)

Layout events all reference a tab_id; the affected WaveObj is the LayoutState referenced by the tab’s layoutstate field. Two SQLite reads chained inside one spawn_blocking to keep the lock hold short.