Update event_bus.py

event_bus.py

@@ -20,6 +20,8 @@ class EventType(Enum):
     # Lifecycle events
     SESSION_STARTED = "session_started"
     SESSION_ENDED = "session_ended"
+    CONVERSATION_STARTED = "conversation_started"
+    CONVERSATION_ENDED = "conversation_ended" 
     
     # STT events
     STT_STARTED = "stt_started"