- 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
swaits