refactor: formaliza formatos de áudio e alinhamento PCM

tests/test_provider_contracts.py

@@ -12,7 +12,6 @@ from voice_assistant.application.events import SpeechChunk
 from voice_assistant.application.voice_session import VoiceSession
 from voice_assistant.domain.session import SessionState
 from voice_assistant.stt.mock import MockSTTAdapter
-from voice_assistant.tts.adapter import TTSAdapter
 from voice_assistant.tts.mock import MockTTSAdapter
 from voice_assistant.turn_manager import TurnManager
 from voice_assistant.voice_pipeline import VoicePipeline
@@ -93,17 +92,17 @@ async def test_streaming_cancellation_releases_stream():
 async def test_stopping_synthesis_early_closes_provider_generator():
     closed = asyncio.Event()
 
-    class TTS(TTSAdapter):
+    class TTS(MockTTSAdapter):
         async def synthesize(self, text):
             try:
-                yield b"audio"
+                yield b"audi"
                 await asyncio.Event().wait()
             finally:
                 closed.set()
 
     pipeline = make_pipeline(MockAgentAdapter(), TTS())
     async with aclosing(pipeline.synthesize_response("Olá")) as stream:
-        assert await anext(stream) == b"audio"
+        assert await anext(stream) == b"audi"
     assert closed.is_set()
 
 
@@ -113,10 +112,10 @@ async def test_interrupt_during_delivery_closes_nonstreaming_tts():
     synthesis_closed = asyncio.Event()
     stt = MockSTTAdapter()
 
-    class TTS(TTSAdapter):
+    class TTS(MockTTSAdapter):
         async def synthesize(self, text):
             try:
-                yield b"audio"
+                yield b"audi"
                 await asyncio.Event().wait()
             finally:
                 synthesis_closed.set()