feat(shield): add Horizon shield

[skarrmann]

Hello! I would like to add a ZMK shield for my open source keyboard, Horizon.
Thank you very much, and please let me know if you have any questions.

Board/Shield Check-list

• This board/shield is tested working on real hardware
• Definitions follow the general style of other shields/boards upstream (Reference)
• .zmk.yml metadata file added
• Proper Copyright + License headers added to applicable files (Generally, we stick to "The ZMK Contributors" for copyrights to help avoid churn when files get edited)
• General consistent formatting of DeviceTree files
• Keymaps do not use deprecated key defines (Check using the upgrader tool)
• &pro_micro used in favor of &pro_micro_d/a if applicable
  • Note: Not applicable
• If split, no name added for the right/peripheral half
  • Note: Not split
• .conf file has optional extra features commented out
  • Note: .conf file is intentionally empty - this board only supports keys

[Nicell]

Hi @skarrmann! Thanks for submitting this shield. Your metadata file is failing the prettier check (instructions to fix are in the build), and I was curious about the availability of this board? Is it purely open-source, is there a GB planned, or is it stocked somewhere?

[skarrmann]

Hi @Nicell - pleasure to meet you! Thank you for reviewing.

I ran prettier:format to fix the metafile, and confirmed that it passes the Prettier check now.

Horizon is print and build it yourself for now, and it's currently a small user base. I know three people who are currently using it, and several people online expressed interest in building it. No group buy or store stocking is planned, but I'm completely open to doing so if there is interest.

If you would prefer shields/boards have a larger user base before they are committed into ZMK proper, I completely understand and would be okay with sharing this shield definition separately.

[Nicell]

@skarrmann Sorry about the late response here. Currently, we're accepting boards that are commercially available, have a completed GB, or are otherwise widely available to lighten the review load for contributors. This shield could use a ZMK config repo instead with the custom definition inside so that users who build themselves can fork and adjust the keymap etc. I would recommend that route for now!

[skarrmann]

Thank you for clarifying @Nicell. I will host this shield in a separate ZMK config repo for the time being. If/when this board has a commercial release, I will submit a PR at that time. Thank you for your time!