Add OpenKNX IDF component with TPUart integration

- Created CMakeLists.txt for the OpenKNX IDF component, ensuring dependencies on OpenKNX and TPUart submodules.
- Implemented Arduino compatibility header for basic functions like millis, delay, pinMode, and digitalRead.
- Developed EspIdfPlatform class for network interface management and multicast communication.
- Added EtsMemoryLoader for loading ETS memory snapshots and managing associations.
- Introduced TpuartUartInterface for UART communication with methods for reading, writing, and managing callbacks.
- Implemented arduino_compat.cpp for Arduino-like functionality on ESP-IDF.
- Created source files for platform and memory loader implementations.
- Updated submodules for knx, knx_dali_gw, and tpuart.

Signed-off-by: Tony <tonylu@tony-cloud.com>

README.md

@@ -12,6 +12,7 @@ This folder hosts the native ESP-IDF C++ rewrite of the Lua DALI gateway.
 	- `dali_domain/`: native DALI domain facade over `dali_cpp` and raw frame sinks.
 	- `gateway_cache/`: DALI scene/group/settings/runtime cache used by controller reconciliation and protocol bridges.
 	- `gateway_bridge/`: per-channel bridge provisioning, command execution, protocol startup, and HTTP bridge actions.
+	- `openknx_idf/`: ESP-IDF port layer for the OpenKNX `gateway/knx` and `gateway/tpuart` submodules, including NVS-backed OpenKNX memory, UDP multicast/unicast plumbing, and a native TP-UART interface without the Arduino framework.
 	- `gateway_modbus/`: gateway-owned Modbus TCP/RTU/ASCII config, generated DALI point tables, and provisioned Modbus model override dispatch.
 	- `gateway_bacnet/`: BACnet/IP server adapter backed by bacnet-stack, including the gateway-owned BACnet bridge model adapter.
 	- `gateway_ble/`: NimBLE GATT bridge for BLE transport parity on `FFF1`/`FFF2`/`FFF3`, including raw DALI notifications.