[ZoomIt] Allow customization of Draw mode pointer size

### Description of the new feature / enhancement

Add an option to adjust the pointer size used in ZoomIt's Draw mode.

### Scenario when this would be used?

During presentations on high-resolution or large displays, the current pointer can be difficult to see from a distance. A configurable pointer size would improve visibility and accessibility.

### Supporting information

This would help users presenting on 4K displays, large monitors, projectors, and conference room screens.

No files, tests, or entry points are named in the issue. Start by locating ZoomIt's Draw mode configuration and pointer-rendering code, then trace how settings are exposed and persisted; done means a user can select a pointer size and see it applied in Draw mode on large displays.

Written by the indexing model from the issue text.