[P2] Scrollbar interaction and input consistency improvements #123
Description
Goal
Improve scrollbar interaction fidelity and usability.
Scope
- Better drag hit-target and hover feedback.
- Smooth wheel/trackpad behavior with consistent step size.
- Ensure scrollbars do not steal input unexpectedly.
Acceptance Criteria
- Dragging scrollbar thumb feels stable and predictable.
- No jitter or jump behavior under fast input.
- Keyboard/mouse/trackpad interactions are consistent.