Fixes [BS-3349](https://linear.app/affine-design/issue/BS-3349/)
<!-- This is an auto-generated comment: release notes by coderabbit.ai -->
## Summary by CodeRabbit
- **New Features**
- Improved edge scrolling during selection dragging for smoother and more responsive viewport navigation.
- Dragging area and mouse position tracking now update reactively with viewport changes, ensuring more accurate selection and movement.
- **Refactor**
- Unified and clarified coordinate handling for dragging and mouse position, with clearer naming and separation between model and browser coordinates.
- Simplified selection logic and removed unnecessary accumulated state for cleaner and more maintainable behavior.
- Enhanced flexibility in coordinate conversion by allowing viewport transformations relative to arbitrary zoom and center.
- Streamlined clipboard paste handling by simplifying mouse position extraction and adjusting attachment options.
- **Bug Fixes**
- Enhanced overlay and dragging area accuracy by updating position calculations and coordinate transformations.
- Fixed paste operations to correctly handle mouse position without unnecessary coordinate conversions.
- Corrected drag initiation positions in toolbar and shape dragging to align with viewport-relative coordinates.
<!-- end of auto-generated comment: release notes by coderabbit.ai -->
In this way, all downstream callers can be guaranteed by correct viewport fit result, instead of requiring them to set `forceUpdate: true` param explicitly to them. The resizing optimization is an internal exception.
doouding