Update AGENTS.md with additional context on implementation and modify pipeline.py to include assistant aggregator in the processing flow.

AGENTS.md

@@ -1 +1,3 @@
-Write readable, maintainable, extensible code for a voice agent endpoint with pipecat as engine
+Write readable, maintainable, extensible code for a voice agent endpoint with pipecat as engine
+
+Write minimal change compare to pipcat official implmentation

engine/pipeline.py

@@ -135,9 +135,9 @@ async def run_pipeline_with_serializer(
             user_aggregator,
             llm,
             ProductTextStreamProcessor(),
-            assistant_aggregator,
             tts,
             transport.output(),
+            assistant_aggregator,
         ]
     )