Add native I2C keyboard support for nRF52840-based devices

[tchellow]

Hello MeshCore team,

I would like to request the addition of native keyboard support, particularly for I2C-based keyboards, targeting nRF52840-based devices (such as Faketec boards and similar platforms).

I am currently using an M5Stack CardKB (I2C keyboard) with an nRF52840-based device. While the hardware supports I2C communication, the keyboard is not recognized or usable in the official MeshCore firmware.

Why this feature would be valuable

• Enables standalone operation on nRF52840 devices
• Reduces dependency on BLE/mobile apps
• Improves usability in field scenarios
• Expands interaction possibilities directly on the device

Suggested scope

• Basic I2C keyboard driver support (scan/input handling)
• Integration with existing input/event system
• Simple text input interface (for messaging and basic commands)

Additional context

Keyboard support already exists in some ESP32-based custom builds (e.g., Cardputer-focused firmware), which shows that this feature is feasible. However, there is currently no equivalent support for nRF52840 platforms in the official firmware.

Willing to help

I’d be happy to assist with testing using my setup (nRF52840 + M5Stack CardKB) or provide feedback if needed.

Thank you for your work on MeshCore.