Rename app_openai.py to app.py

app_openai.py → app.py

@@ -44,7 +44,7 @@ def respond(
     response_text = ""
     try:
         response = client.chat.completions.create(
-            model="gpt-4o",  # or "gpt-4o-mini" when available
+            model="gpt-4o-mini",  # or "gpt-4o" if mini unavailable
             messages=messages,
             max_tokens=max_tokens,
             temperature=temperature,