Add PID 1209/7709 for Nb.1

[n4subishin]

Requesting PID 1209/0709 for Nb.1, a 12-position programmable macropad.

• Project: https://github.com/n4subishin/nb1-keyboard
• License: GPL-2.0
• Hardware: KiCad schematic and PCB layout are published in hardware/
• Firmware: QMK Firmware based, sources under keyboards/nb1/

Both the PCB design and the firmware are open source under GPL-2.0, so the
source URL covers the full design as required.

The board is built around an STM32F405RGT6. Each of the 12 positions shares a
single footprint that accepts either a Cherry MX compatible switch or a rotary
encoder, so the same PCB can be assembled as keys, knobs, or any mix.

This is my first PID request. Please let me know if anything needs to be
corrected.

[cnlohr]

I have no way to retrigger CI, can you either make a new commit or reopen the PR, @n4subishin ?

[cnlohr]

Additionally, @n4subishin can you include one of (or preferably both) a PDF/PNG of the schematic and/or a picture of the hardware that is your project? Please @ me in thread when you have done this so I can quickly respond.

[n4subishin]

@cnlohr Thanks for the review, and sorry for the delay. Both checks are
passing now.

Two things changed since you last looked:

• The PID file was in the wrong place (org/n4subishin/1209/0709/). It now
  sits at 1209/7709/.
• The PID itself changed from 0709 to 7709 — the validator rejects 0x0xxx
  as reserved. The PR title is updated to match.

I have also added both a PDF of the schematic and a photo of the assembled
hardware to the project repository:

• Schematic (PDF): https://github.com/n4subishin/nb1-keyboard/blob/main/hardware/schematic.pdf
• Photo: https://github.com/n4subishin/nb1-keyboard/blob/main/hardware/photo.jpg

The board is a 12-position macropad built around an STM32F405RGT6, running QMK
Firmware. Both the KiCad design files and the firmware sources are published in
the same repository under GPL-2.0.

Photo attached below for convenience.