Add NuPhy Air60 V2 keyboard

[carbonarok]

Summary

• Add support for the NuPhy Air60 V2, a tri-mode wireless 64-key ANSI keyboard (USB + 2.4GHz RF + Bluetooth x3)
• STM32F072 MCU with dual IS31FL3733 RGB drivers (48 + 26 LEDs, including 10 side indicator LEDs)
• Wireless communication via UART to secondary NRF module at 460800 baud
• Custom side LED animations for status indicators (battery, connectivity, mode)

Hardware Details

• MCU: STM32F072
• RGB: 2x IS31FL3733 (74 total LEDs — 64 per-key + 10 side)
• Wireless: NRF module over UART (2.4GHz RF + BLE x3)
• Bootloader: STM32-DFU

Features

• Full RGB matrix with per-key and side LED control
• Tri-mode wireless switching (USB / RF / BLE1-3) via custom keycodes
• OS Detection for automatic Mac/Windows key behavior
• Sleep/wake power management for wireless mode
• Battery level display on side LEDs

Test Plan

• Compiles with qmk compile -kb nuphy/air60_v2/ansi -km default
• Passes qmk lint -kb nuphy/air60_v2/ansi
• USB mode: typing, NKRO, RGB matrix effects
• Wireless mode: RF and BLE1-3 pairing/switching
• Side LED animations and battery indicator
• Sleep/wake cycle in wireless mode
• OS Detection: correct modifier keys on macOS vs Windows
• Bootmagic reset (hold Escape + plug in)