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

Documentation/README.md

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+# RNode Documentation