change transcription model

self_hosted_env/voice_agent/core/enums.py

@@ -17,7 +17,7 @@ class StudentNationality(str, Enum):
 
 
 class Models(str, Enum):
-    chat = "gpt-5-nano"
+    chat = "gpt-5"
     tts = "gpt-4o-mini-tts"
     embedding = "text-embedding-3-small"
-    transcription = "whisper-1"
+    transcription = "gpt-4o-transcribe"