docs: Add SAUL-TEE system reference + update wiring diagram
- docs/SAUL-TEE-SYSTEM-REFERENCE.md: authoritative architecture doc for
the new 4-wheel wagon. Covers ESP32-S3 BALANCE (Waveshare LCD 1.28,
QMI8658, SN65HVD230 CAN), ESP32-S3 IO (TBS Crossfire, ELRS, BTS7960,
NFC/baro/ToF, WS2812), inter-board UART protocol (460800 baud,
[0xAA][len][type][payload][crc8]), CAN IDs (VESCs 68/56, Orin
0x300-0x303 cmd / 0x400-0x401 telemetry), RC channel map, power
architecture, safety systems, and firmware layout.
- docs/wiring-diagram.md: banner pointing to new reference doc;
old Mamba F722S UART summary marked OBSOLETE.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
sl-mechanical
bfca6d1d92