The OpenAI Chat Completions API defaults `stream` to false, but ChatRequest.stream
was defaulting to True. As a result, any standard OpenAI-compatible client that
omits the `stream` field receives a `text/event-stream` response where it expects
plain JSON, and fails with:
AttributeError: 'str' object has no attribute 'choices'
Reproduce (openai==1.59.6):
from openai import OpenAI
c = OpenAI(base_url='http://localhost:8998/v1', api_key='none')
c.chat.completions.create(model='minimind', messages=[{'role':'user','content':'hi'}])
curl with an explicit "stream": false returns correct JSON, confirming the handler
logic is fine and only the default value is at fault.
Explicit `stream=True` requests are unaffected.