Switch to simple blue LED indicator on GPIO8

C3 Super Mini has a plain blue LED on GPIO8, not an addressable
WS2812B. Removed NeoPixel library, using digitalWrite instead.
LED on = Loki active and chaffing.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/main.cpp

@@ -7,6 +7,8 @@
 
 #include <Arduino.h>
 #include <NimBLEDevice.h>
+// ── Blue status LED on GPIO8 ──
+#define LED_PIN 8
 
 // ── Device profiles ──
 
@@ -102,6 +104,10 @@ void setup() {
     Serial.println("=============================");
     Serial.println();
 
+    // Blue LED — Loki is active
+    pinMode(LED_PIN, OUTPUT);
+    digitalWrite(LED_PIN, HIGH);
+
     NimBLEDevice::init("");
     NimBLEDevice::setOwnAddrType(BLE_OWN_ADDR_RANDOM);