MidnightNameplates Phase 8.0.3 - Draggable Scrollbars

Fixed globally for every config page:
- Scrollbar thumb can now be dragged with the left mouse button.
- Mouse wheel scrolling still works.
- Clicking the scrollbar track jumps toward that position.
- Drag math follows the real content height and viewport height.
- Classifications and Unit Types benefit automatically because they use the same NewPage scroll component.

Next roadmap phase:
Phase 8.1 - Optional Target Marker System.
