Port the Wio Tracker L1 solo firmware (full on-device UI, dual BLE/USB
companion transport) to Heltec V3 and V4 OLED boards. Neither board has
a joystick or CardKB on-board, so each new env wires up both as optional
peripherals with default pins from what the board leaves free, gated
behind the existing UI_HAS_JOYSTICK/ENV_PIN_SDA+SCL flags.
DUAL_SERIAL was nRF52-only; added an ESP32 helpers/esp32/DualSerialInterface.h
counterpart so the flag isn't silently ignored on these boards. On V4's
native USB CDC, isClientConnected() also honours (bool)Serial (real DTR),
same as the nRF52 version; V3 has no native CDC so it stays BLE-only there.
Screen (SDA 17/SCL 18) and CardKB (SDA 3/SCL 4) confirmed working on real
V4 hardware.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
JakubandClaude Sonnet 5
2bde84a573