pipecat/changelog/+realtime-service-mode-events.added.md

• Added on_user_message_added and on_assistant_message_added event handlers on LLMUserAggregator and LLMAssistantAggregator. Each fires when its respective message is flushed to context and carries the finalized content. In cascade mode they coincide with on_user_turn_stopped / on_assistant_turn_stopped; in realtime mode (where turn-stop fires before the message is finalized) they're the canonical way to subscribe to "context just updated, here's the text."