Initial commit: RNodeTHV4 boundary mode firmware for Heltec V4

Bridges LoRa mesh and TCP/WiFi backbone networks using microReticulum.
Based on microReticulum_Firmware with boundary mode additions:
- BoundaryMode.h: State management and EEPROM persistence
- BoundaryConfig.h: WiFi captive portal for configuration
- TcpInterface.h: TCP backbone interface with HDLC framing
- Display.h: Custom OLED layout with network status indicators
- Transport/Identity library patches for embedded memory constraints

variants/rak11300/rak_variant.cpp

@@ -0,0 +1 @@
+#include "rak_variant.h"

variants/rak11300/rak_variant.h

@@ -0,0 +1,6 @@
+#pragma once
+#include <stdint.h>
+#ifndef _VARIANT_RAK11300_
+#define _VARIANT_RAK11300_
+
+#endif // #define _VARIANT_RAK11300_

variants/rak11300/variant.h

@@ -0,0 +1,2 @@
+// Just for consistency, for RAK11310 all definitions are in the pins_arduino.h
+#include "rak_variant.h"