- Each board now exports DisplayDriver type and create_display() async fn
- ESP32-S3 boards share SSD1306 create_display in board/esp32s3.rs
- RAK WisBlock has its own SSD1306 create_display (different I2C type)
- Wio Tracker has SH1106 create_display (different display IC)
- Removed all cfg_if from display.rs — calls board::create_display()
- Removed display init retry logic (single attempt, return None on failure)
- ZERO board-specific #[cfg(feature)] outside board/, host/mod.rs, and hal/
- Flattened radio/ directory to radio.rs (was just one file)
- Flattened display/ to display.rs (combined task + rendering as inline module)
- Moved SH1106 display driver reference from display/ to driver/ (done in Phase 2)
- Suppressed dead_code warnings for conditional USB/UART types in hal
- All boards: zero warnings, zero cfg in application code
- Created host/ module with internal cfg dispatch (USB vs UART)
- Moved usb/task.rs → host/usb.rs, uart/task.rs → host/uart.rs
- Moved protocol_io.rs → host/framing.rs
- Renamed usb_task/uart_task to host_task (uniform name)
- Removed all host-comm cfg from main.rs
- The run() function now has ZERO board-specific conditional compilation
- Deleted old usb/, uart/, protocol_io.rs modules
- Created hal/esp32s3.rs with MCU primitives (SPI, I2C, USB, UART, timer, MAC)
- Created hal/nrf52840.rs with shared nRF boilerplate (interrupts, bus wrapping, VBUS, MAC)
- Moved SH1106 OLED driver from display/ to driver/ (clear separation from app code)
- Board esp32s3.rs now delegates MCU init to hal, keeps only peripheral wiring (RadioParts)
- nRF board files use hal for shared StaticCell patterns, mac_address, interrupt bindings
- Board files still own pin assignments and peripheral construction
- Made protocol_io.rs compile for all boards (not just heltec_v3)
- Renamed FrameAccumulator → CobsDecoder, encode_response → cobs_encode_response
- Refactored USB task to use shared CobsDecoder and route_command from protocol_io
- Removed ~80 lines of duplicated COBS framing and command routing from usb/task.rs
- Single canonical MAX_FRAME definition in protocol_io.rs
swaits