Add initial ESP32 controller firmware

firmware/esp32/xterra-controller/relays.cpp

@@ -0,0 +1,17 @@
+#include <Arduino.h>
+#include "config.h"
+#include "relays.h"
+
+RelayState relays;
+
+void initRelays() {
+    pinMode(RELAY_STARLINK_PIN, OUTPUT);
+    pinMode(RELAY_FRIDGE_PIN, OUTPUT);
+
+    updateRelayOutputs();
+}
+
+void updateRelayOutputs() {
+    digitalWrite(RELAY_STARLINK_PIN, relays.starlink);
+    digitalWrite(RELAY_FRIDGE_PIN, relays.fridge);
+}