Add Split-Ball 34mm Trackball part with ZMK/QMK variants

[SkreeCustomKeyboards]

Added the QMK and ZMK versions for the split ball style trackball mount. 34mm is only available as I need to figure out how to scale without effecting (probably repositioning correctly) the bearing holes and threads.

These use the resin cup and then have 3.5mm ceramic bearings installed from the bottom of the cup. Hex set screws are used to set the bearing 'depth'. This lets you use calipers to very accurately adjust the sensor to trackball position.

Added links to the BOM / part description too.

I don't have the site cup listings up just yet but will sometime tomorrow.

[vercel]

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Project	Deployment	Actions	Updated (UTC)
cosmos-keyboards	Ready	Preview	Jul 7, 2026 7:00pm

[rianadon]

Looks great. I'm a little worried about the margin between the bottom cup and the web. Because your 3d model is shorter than the 4mm web you defined, the web and cup are going to touch at the top. It might be worth increasing the socket's outer radius by 0.5mm or so (or alternatively shrinking the cup by the same amount) so that there's more tolerance.

Other nits:

• The formatting check raised an issue
• Please use different icons for the extraBomItems. There's a pcb icon for PCBs which is probably a good fit for the sensor. For the cup I'd just use a literal cup. You edit Icon.svelte to add new icons.
• I have some changes coming to geometry intersection checking. It's unreleased but on the github, so I'd appreciate if you could add the parts for that. Documentation is here: https://github.com/rianadon/Cosmos-Keyboards/blob/main/docs/docs/contributing.md#intersection-geometry. You can probably reuse the stuff I did for the existing trackballs. The only difference for you is that you'd leave simpleSocketGeos alone as the trackball cup is part of the part, not the socket. simplePartGeos would return both the outer shell of the cup using the botIcosahredron function and the trackball itself.