Two mirrored halves plus a numpad that carries the USB hub. Captures the
architecture decisions and the reasoning behind them: CH32L103 with an
STM32F103 pin-compatible escape hatch, split protocol tunnelled over USB-C
SBU through the numpad, hotswap sockets bottom-side, and why crystal-less
USB was ruled out across the whole WCH catalogue.
No boards ordered, no firmware written. Layout still undesigned.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>