[Feature Request] Some navigation improvements

I think Helvum is a pretty neat tool to easily visualize Pipewire managing resources in the background. However actually using Helvum is still not a great experience from a user perspective.

I think it is necessary to navigate somehow with the mouse (using middle-mouse-button or right-mouse-button to drag the view of elements around for example). Because using the scrollbars is not a good option, really. It's fine as fallback but not a solution.

Maybe the scrollbars already work fine for a touchscreen. I haven't tried that yet but for a mouse, I think, dragging a view around is the best option (I'm used to this from node visualizations in Carla and Blender for example).