Fix for chat response auto scroll :
### Benefits
- More reliable auto-scrolling during streaming
- Better handling of user scroll interactions
- Improved mobile device support
- Smoother initial load with instant scroll
- Cleaner code organization and maintainability
### Testing
The changes can be verified by:
1. Loading chat - should instantly scroll to bottom
2. Streaming messages - should smoothly auto-scroll
3. Manual scroll up - should stay at user's position
4. Scroll to bottom - should resume auto-scroll
5. Mobile testing - should work with touch interactions
