refactor: LoRaBoard trait with full associated types + BoardParts

- LoRaBoard trait now has associated types: RadioParts, CommParts, DisplayParts, DisplayDriver
- into_parts() is on the trait (enforced by compiler, not implicit convention)
- BoardParts<R, C, D> struct replaces tuple return from into_parts()
- mac_address() stays on trait, MAC also in BoardParts for convenience
- Removed mac field from DisplayParts (display task calls Board::mac_address())
- DisplayDriver associated type requires DrawTarget<Color = BinaryColor>

src/board/heltec_v3.rs

@@ -1,17 +1,15 @@
 use esp_hal::gpio::{Level, Output, OutputConfig};
 
 use super::esp32s3;
-use super::traits::LoRaBoard;
+use super::traits::{BoardParts, LoRaBoard};
 use crate::hal::esp32s3 as mcu;
 
-#[allow(unused_imports)] // Re-exported for other modules (display, radio, uart tasks)
+#[allow(unused_imports)] // Re-exported for other modules (display, radio, host tasks)
 pub use super::esp32s3::{
     create_display, DisplayDriver, DisplayI2c, DisplayParts, RadioDriver, RadioParts, UartDriver,
     UartParts,
 };
 
-// ── Board init ──────────────────────────────────────────────────────
-
 pub struct Board {
     p: esp_hal::peripherals::Peripherals,
 }
@@ -20,6 +18,11 @@ impl LoRaBoard for Board {
     const NAME: &'static str = "Heltec V3";
     const TX_POWER_RANGE: (i8, i8) = (-9, 22);
 
+    type RadioParts = RadioParts;
+    type CommParts = UartParts;
+    type DisplayParts = DisplayParts;
+    type DisplayDriver = DisplayDriver;
+
     fn init() -> Self {
         let p = esp_hal::init(esp_hal::Config::default());
         Self { p }
@@ -28,21 +31,19 @@ impl LoRaBoard for Board {
     fn mac_address() -> [u8; 6] {
         mcu::mac_address()
     }
-}
 
-impl Board {
-    pub fn into_parts(self) -> (RadioParts, UartParts, Option<DisplayParts>) {
+    fn into_parts(self) -> BoardParts<RadioParts, UartParts, DisplayParts> {
         let p = self.p;
 
         mcu::start_timer(p.TIMG0);
 
         // Vext power: GPIO36, active LOW to enable peripherals
         let vext = Output::new(p.GPIO36, Level::Low, OutputConfig::default());
-        core::mem::forget(vext); // hold pin low permanently; drop would reset it
+        core::mem::forget(vext);
 
         let spi_bus = mcu::init_spi(p.SPI2, p.DMA_CH0, p.GPIO9, p.GPIO10, p.GPIO11);
         let radio = esp32s3::init_radio(spi_bus, p.GPIO8, p.GPIO12, p.GPIO14, p.GPIO13);
-        let uart = UartParts {
+        let host = UartParts {
             driver: mcu::init_uart(p.UART0, p.GPIO43, p.GPIO44),
         };
 
@@ -51,12 +52,16 @@ impl Board {
         esp_hal::delay::Delay::new().delay_millis(10);
         display_rst.set_high();
         esp_hal::delay::Delay::new().delay_millis(10);
-        core::mem::forget(display_rst); // hold reset high permanently
+        core::mem::forget(display_rst);
 
         let i2c = mcu::init_i2c(p.I2C0, p.GPIO17, p.GPIO18);
-        let mac = Self::mac_address();
-        let display = Some(DisplayParts { i2c, mac });
+        let display = Some(DisplayParts { i2c });
 
-        (radio, uart, display)
+        BoardParts {
+            radio,
+            host,
+            display,
+            mac: Self::mac_address(),
+        }
     }
 }