feat: add session updates and message dialogs

backend/services/pipecat/pipeline.py

@@ -74,6 +74,7 @@ from services.pipecat.processors import (
     PassthroughLLMAssistantAggregator,
     RealtimeDynamicVariableProcessor,
     RealtimeUserInputProcessor,
+    SessionUpdateProcessor,
     UserInput,
     UserInputProcessor,
     UserTurnRoutingProcessor,
@@ -365,6 +366,10 @@ async def run_pipeline(
             or tool_interruption_strategy.is_muted
         )
     )
+    session_update = SessionUpdateProcessor(
+        brain.on_session_update,
+        should_ignore_update=lambda: call_end.ending,
+    )
     client_tools = ClientToolBroker()
     vision_capture = VisionCaptureProcessor()
     knowledge_retrieval = KnowledgeRetrievalProcessor(
@@ -578,6 +583,7 @@ async def run_pipeline(
         [
             transport.input(),
             client_tools,
+            session_update,
             vision_capture,
             user_input,
             stt_processor,
@@ -778,6 +784,16 @@ async def run_realtime_pipeline(
     input_sample_rate, output_sample_rate = realtime_audio_sample_rates(cfg)
     user_input = RealtimeUserInputProcessor()
     dynamic_variables = RealtimeDynamicVariableProcessor(brain, cfg, realtime)
+
+    async def refresh_realtime_instructions() -> None:
+        update = getattr(realtime, "update_instructions", None)
+        if callable(update):
+            await update(brain.system_prompt(cfg))
+
+    session_update = SessionUpdateProcessor(
+        brain.on_session_update,
+        after_update=refresh_realtime_instructions,
+    )
     greeting = await brain.greeting(cfg)
 
     recorder = await ConversationRecorder.start(
@@ -790,6 +806,7 @@ async def run_realtime_pipeline(
     pipeline = Pipeline(
         [
             transport.input(),
+            session_update,
             user_input,
             realtime,
             dynamic_variables,