refactor: formaliza formatos de áudio e alinhamento PCM

tests/test_protocol.py

@@ -18,7 +18,7 @@ Non-responsibilities:
 
 import pytest
 from pydantic import ValidationError
-from voice_assistant.audio.models import CANONICAL_AUDIO_FORMAT
+from voice_assistant.audio.models import AudioFormat, CANONICAL_AUDIO_FORMAT
 from voice_assistant.audio_gateway.app.protocol import (
     AgentDelta,
     AgentResponse,
@@ -83,6 +83,7 @@ def test_session_ready_output():
         protocol_version="1.0",
         session_id="session-1",
         audio=CANONICAL_AUDIO_FORMAT,
+        output_audio=AudioFormat(encoding="pcm_s16le", sample_rate=48000, channels=1),
     )
 
     assert event.model_dump() == {
@@ -94,6 +95,11 @@ def test_session_ready_output():
             "sample_rate": 16000,
             "channels": 1,
         },
+        "output_audio": {
+            "encoding": "pcm_s16le",
+            "sample_rate": 48000,
+            "channels": 1,
+        },
     }