Support trackpad regions as axis inputs/sliders

No idea if this is possible (I'm not sure what the browser gets access to), but it'd be really cool to be able to assign regions of the trackpad as input sliders for controls, e.g. if I slide my finger up/down the right edge then I can make my lights1 dimmer/brighter, but if I do it on the left edge it does lights2 instead...

We could also then have the left and right halves of the trackpad used for motion control, which could be useful for testing purposes, or in emergencies if the joystick dies or something.

Start by checking the browser input APIs available to the TypeScript/Vue application and how existing axis inputs or sliders are represented. Define whether trackpad regions can be mapped reliably to separate controls or motion inputs, then verify that the proposed mappings work across the supported platforms.

Written by the indexing model from the issue text.