LED refactor + RAK reversed polarity fix

zephcore/boards/example_board/README.md

@@ -280,3 +280,21 @@ All XIAO boards use the same D-pin assignment for Wio-SX1262:
 
 Note: nRF52840 D-pin mapping varies by board (XIAO nRF52840 shown).
 RAK4631 has SX1262 integrated — different pinout entirely.
+
+
+RAK4631 user LEDs (upstream board + overlay)
+--------------------------------------------
+
+ZephCore’s `boards/nrf52840/rak4631/board.overlay` augments Zephyr’s stock RAK4631
+definition. Future changes to that overlay should keep the following in mind:
+
+**Polarity:** Upstream Zephyr marks the WisBlock user LEDs (`green_led` / `blue_led`
+on P1.3 / P1.4) as `GPIO_ACTIVE_LOW`. On actual RAK4631 + base-board hardware they
+match MeshCore / Arduino (`LED_STATE_ON` = HIGH). If the polarity in devicetree is
+wrong, both LEDs stay **on** most of the time and the heartbeat looks like a **short
+off** pulse (inverted). Override both nodes in the overlay with `GPIO_ACTIVE_HIGH`.
+
+**Aliases:** Upstream defines only `led0` → blue. ZephCore sets `led0` → green
+(heartbeat), `led1` → blue (companion unread pulse), and `lora-tx-led` → blue (LoRa
+TX activity). Repeaters disable the unread-LED path in firmware so blue is TX-only
+alongside green heartbeat.

zephcore/boards/nrf52840/rak4631/board.overlay

@@ -29,7 +29,11 @@
 
 / {
 	aliases {
-		led1 = &green_led;
+		/* Upstream: led0=blue only. ZephCore: green=heartbeat (led0), blue=unread+TX flash.
+		 * lora-tx-led drives blue during LoRa TX (repeater: TX-only on blue; companion: + msg). */
+		led0 = &green_led;
+		led1 = &blue_led;
+		lora-tx-led = &blue_led;
 	};
 	chosen {
 		zephyr,code-partition = &code_partition;
@@ -71,6 +75,15 @@
        rx-boosted;
 };
 
+/* Upstream board uses GPIO_ACTIVE_LOW; hardware matches MeshCore Arduino LED_STATE_ON=HIGH. */
+&green_led {
+	gpios = <&gpio1 3 GPIO_ACTIVE_HIGH>;
+};
+
+&blue_led {
+	gpios = <&gpio1 4 GPIO_ACTIVE_HIGH>;
+};
+
 /*
  * GPS on UART0 - RAK1910 (u-blox MAX-7Q) at 9600 baud
  * Connect to Slot A (UART pins P0.19 RX, P0.20 TX)