Add command interface and status indicator.

src/core/history.rs

@@ -34,6 +34,11 @@ impl ConversationHistory {
     pub fn messages(&self) -> &[ConversationMessage] {
         &self.messages
     }
+
+    /// Remove all messages from the history.
+    pub fn clear(&mut self) {
+        self.messages.clear();
+    }
 }
 
 impl Default for ConversationHistory {
@@ -73,6 +78,17 @@ mod tests {
         assert_eq!(msgs[1].content, "hi there");
     }
 
+    #[test]
+    fn clear_empties_history() {
+        let mut history = ConversationHistory::new();
+        history.push(ConversationMessage {
+            role: Role::User,
+            content: "hello".to_string(),
+        });
+        history.clear();
+        assert!(history.messages().is_empty());
+    }
+
     #[test]
     fn messages_preserves_insertion_order() {
         let mut history = ConversationHistory::new();