Fix Supertone API URL: api.supertone.ai -> supertoneapi.com

tts.py

@@ -150,7 +150,7 @@ def predict_supertone_tts(text: str, model: str = "sona_speech_1") -> str:
     voice_id = SUPERTONE_VOICE_ID
     
     response = requests.post(
-        f"https://api.supertone.ai/v1/text-to-speech/{voice_id}?output_format=wav",
+        f"https://supertoneapi.com/v1/text-to-speech/{voice_id}",
         headers={
             "x-sup-api-key": api_key,
             "Content-Type": "application/json",
@@ -159,6 +159,7 @@ def predict_supertone_tts(text: str, model: str = "sona_speech_1") -> str:
             "text": text,
             "language": "ko",
             "model": model,
+            "output_format": "wav",
             "voice_settings": {
                 "pitch_shift": 0,
                 "pitch_variance": 1,