Add command interface and status indicator.

src/core/orchestrator.rs

@@ -65,6 +65,9 @@ impl<P: ModelProvider> Orchestrator<P> {
         while let Some(action) = self.action_rx.recv().await {
             match action {
                 UserAction::Quit => break,
+                UserAction::ClearHistory => {
+                    self.history.clear();
+                }
 
                 UserAction::SendMessage(text) => {
                     // Push the user message before snapshotting, so providers