refactor: replace Qwen 1.7B with Qwen3-TTS 0.6B as default Qwen TTS engine

test_qwen_tts_service.py

@@ -1,7 +1,7 @@
 """test_qwen_tts_service.py
 
 Unit test for QwenTTSService.
-Verifies loading MLX Qwen3-TTS 1.7B model and generating audio frames.
+Verifies loading MLX Qwen3-TTS 0.6B model and generating audio frames.
 """
 
 import asyncio
@@ -10,11 +10,11 @@ from pipecat.frames.frames import TTSAudioRawFrame
 
 
 async def main():
-    print("Testing QwenTTSService with MLX Qwen3-TTS 1.7B...")
+    print("Testing QwenTTSService with MLX Qwen3-TTS 0.6B...")
     service = QwenTTSService(voice="qwen_jv")
 
     frames = []
-    async for frame in service.run_tts("Hello! This is a test of Qwen 1.7B TTS service.", context_id="test_ctx"):
+    async for frame in service.run_tts("Hello! This is a test of Qwen 0.6B TTS service.", context_id="test_ctx"):
         frames.append(frame)
 
     assert len(frames) > 0, "No frames generated by QwenTTSService"