bug: Can't cancel token streaming mid run

[dinhlongviolin1]

Version: dev branch

Describe the Bug

With the new introduction of the new scheduler for token streaming, now if you try to cancel mid run, the entire application freezes.

Steps to Reproduce

1. Send a message
2. Wait for the message to be processed and stream
3. Click cancel and see that it is freezing

Screenshots / Logs

Screen_Recording_2025-08-19_at_01.49.14.mov

Operating System

• MacOS
• Windows
• Linux