Add Wolf Singa Kohaku Hotswap, Solder, and Solder RGB

[amorino]

Description

Add VIA support for the Wolf Singa Kohaku in three variants:

• Kohaku Hotswap (0x5453/0x0300)
• Kohaku Solder (0x5453/0x0301)
• Kohaku Solder RGB (0x5453/0x0303)

V3 definitions added under v3/wolf/singa/kohaku/.

The JSONs are the official JSONs distributed by SINGAKBD in https://singakbd.com/pages/downloads

QMK Pull Request

qmk/qmk_firmware#26105

VIA Keymap Pull Request

the-via/qmk_userspace_via#146

Checklist

• The VIA support for this keyboard is MERGED in QMK master already (MANDATORY)
• VIA keymap is MERGED in VIA userspace master already (MANDATORY)
• The VIA definition follows the guide here: https://caniusevia.com/docs/layouts
• I have a V3 JSON version for this keyboard definition.(MANDATORY)
• I have formatted the JSON file to have consistent formatting with the rest of the repository.
• I have tested this keyboard definition using VIA's "Design" tab.
• I have tested this keyboard definition with firmware on a device.
• I have assigned alpha keys and modifier keys with the correct colors.
• The Vendor ID is not 0xFEED