Remove arduino-esp32 dependency, modernise WiFi and SPI compat

- Replace Arduino WiFi.h in Networking.cpp with native esp_wifi/esp_netif;
  uses event-driven connect with FreeRTOS EventGroup and 30 s timeout
- Remove initArduino() / Arduino.h from main.cpp
- Remove deprecated arduino-esp32 submodule (was uninitialized and marked
  deprecated since it was first added in Dec 2021)
- rc522.h: guard VSPI_HOST → SPI3_HOST for ESP-IDF 5.x compatibility
- WebInterface.cpp: drop redundant esp_wifi.h (esp_netif.h is sufficient)
- CMakeLists.txt: add esp_wifi + nvs_flash to REQUIRES

https://claude.ai/code/session_01MhAnh68DPNnTjcKqjNYDmk

device/main/main.cpp

@@ -1,5 +1,3 @@
-#include "Arduino.h"
-
 #include "Networking.hpp"
 #include "WebInterface.hpp"
 #include "RFIDInterface.hpp"
@@ -25,8 +23,6 @@ std::shared_ptr<CacheManager>   cacheManager;
 std::shared_ptr<TagPlayerControl> tagPlayerControl;
 
 void app_main(void) {
-    initArduino();
-
     /* SD card must be mounted first — other components depend on it */
     webInterface.initSD();