refactor: unify SimpleLed via embedded-hal, remove Option<L> from BoardParts

- Added embedded-hal 1.0 as direct dep (already transitive via embedded-hal-async)
- SimpleLed<P: OutputPin> now generic over any HAL — single definition in driver/
- Removed duplicate SimpleLed from board/esp32s3.rs and board/wio_tracker_l1.rs
- Changed BoardParts.led from Option<L> to L — boards with no LED use ()
- Display task calls led.set_rgb() unconditionally (no-op for () boards)
- RAK board: led: () instead of led: None

Cargo.lock

@@ -390,6 +390,7 @@ dependencies = [
  "embassy-usb",
  "embassy-usb-driver",
  "embedded-graphics",
+ "embedded-hal 1.0.0",
  "embedded-hal-async",
  "embedded-io-async 0.7.0",
  "esp-backtrace",