TriChord: supported models and connection guides

TriChord models are F60w, Manta40 rev2 and Manta40 rev2 Ortho, supporting USB / 2.4G / BLE. Use these guides for daily operations:

• Unbox and connect: power, switching and pairing
• Full TriChord operations: keys, clearing pairing, audio and UF2
• 2.4G receiver configuration and reset

STM32L412 handles scanning and USB; CH592 handles wireless. TriChord firmware is not interchangeable with AVR Bluefruit / DuoChord / CH592 firmware, or between F60w, Manta40 rev2 and Ortho.