- device_ws.py: dispatch home_request/popup_request to HomeFormatter/PopupFormatter
via async tasks; each request gets a UUID request_id for frame correlation
- chat.py: remove chat_stream WS endpoint (superseded by unified device WS);
keep POST /chat REST fallback unchanged
- 5 new integration tests pass; all 22 existing device_ws tests still pass
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
