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/components/esp-idf-rc522/rc522.h

@@ -10,7 +10,12 @@ extern "C" {
 #define RC522_DEFAULT_MOSI                 (23)
 #define RC522_DEFAULT_SCK                  (19)
 #define RC522_DEFAULT_SDA                  (22)
-#define RC522_DEFAULT_SPI_HOST             (VSPI_HOST)
+/* VSPI_HOST was renamed to SPI3_HOST in ESP-IDF 5.0 */
+#ifdef VSPI_HOST
+#  define RC522_DEFAULT_SPI_HOST           (VSPI_HOST)
+#else
+#  define RC522_DEFAULT_SPI_HOST           (SPI3_HOST)
+#endif
 #define RC522_DEFAULT_SCAN_INTERVAL_MS     (125)
 #define RC522_DEFAULT_TACK_STACK_SIZE      (4 * 1024)
 #define RC522_DEFAULT_TACK_STACK_PRIORITY  (4)

device/main/CMakeLists.txt

@@ -9,4 +9,4 @@ idf_component_register(SRCS
         "BluetoothInterface.cpp"
         "audio_setup.c"
     INCLUDE_DIRS "."
-    REQUIRES esp_http_client esp_netif)
+    REQUIRES esp_http_client esp_netif esp_wifi nvs_flash)

device/main/Networking.cpp

@@ -1,26 +1,89 @@
 #include "Networking.hpp"
 
-#include "WiFi.h"
 #include <esp_log.h>
+#include <esp_wifi.h>
+#include <esp_event.h>
+#include <esp_netif.h>
+#include <nvs_flash.h>
+#include <freertos/FreeRTOS.h>
+#include <freertos/event_groups.h>
+#include <string.h>
 
 static const char* TAG = "Networking";
 
-static constexpr int WIFI_TIMEOUT_MS = 30000;
-static constexpr int WIFI_POLL_MS    = 500;
+static EventGroupHandle_t s_wifi_event_group;
+static const int CONNECTED_BIT = BIT0;
+static int s_retries = 0;
 
-void Networking::connectWifi() {
-    WiFi.begin(CONFIG_ESP_WIFI_SSID, CONFIG_ESP_WIFI_PASSWORD);
-
-    int elapsed = 0;
-    while(WiFi.status() != WL_CONNECTED && elapsed < WIFI_TIMEOUT_MS) {
-        vTaskDelay(WIFI_POLL_MS / portTICK_PERIOD_MS);
-        elapsed += WIFI_POLL_MS;
-        ESP_LOGI(TAG, "Waiting for WiFi... (%d ms)", elapsed);
-    }
-
-    if(WiFi.status() == WL_CONNECTED) {
-        ESP_LOGI(TAG, "Connected. IP: %s", WiFi.localIP().toString().c_str());
-    } else {
-        ESP_LOGW(TAG, "WiFi connection timed out — running without network");
+static void wifi_event_handler(void*, esp_event_base_t base, int32_t id, void* data) {
+    if(base == WIFI_EVENT && id == WIFI_EVENT_STA_START) {
+        esp_wifi_connect();
+    } else if(base == WIFI_EVENT && id == WIFI_EVENT_STA_DISCONNECTED) {
+        if(s_retries < CONFIG_ESP_MAXIMUM_RETRY) {
+            esp_wifi_connect();
+            s_retries++;
+            ESP_LOGI(TAG, "Reconnect attempt %d/%d", s_retries, CONFIG_ESP_MAXIMUM_RETRY);
+        } else {
+            ESP_LOGW(TAG, "Could not connect after %d attempts", CONFIG_ESP_MAXIMUM_RETRY);
+        }
+    } else if(base == IP_EVENT && id == IP_EVENT_STA_GOT_IP) {
+        ip_event_got_ip_t* ev = (ip_event_got_ip_t*)data;
+        ESP_LOGI(TAG, "Connected. IP: " IPSTR, IP2STR(&ev->ip_info.ip));
+        s_retries = 0;
+        xEventGroupSetBits(s_wifi_event_group, CONNECTED_BIT);
     }
 }
+
+void Networking::connectWifi() {
+    /* NVS is required by the WiFi driver */
+    esp_err_t err = nvs_flash_init();
+    if(err == ESP_ERR_NVS_NO_FREE_PAGES || err == ESP_ERR_NVS_NEW_VERSION_FOUND) {
+        nvs_flash_erase();
+        nvs_flash_init();
+    }
+
+    err = esp_netif_init();
+    if(err != ESP_OK && err != ESP_ERR_INVALID_STATE) {
+        ESP_LOGE(TAG, "esp_netif_init: %s", esp_err_to_name(err));
+    }
+
+    err = esp_event_loop_create_default();
+    if(err != ESP_OK && err != ESP_ERR_INVALID_STATE) {
+        ESP_LOGE(TAG, "esp_event_loop_create_default: %s", esp_err_to_name(err));
+    }
+
+    esp_netif_create_default_wifi_sta();
+
+    wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+    esp_wifi_init(&cfg);
+
+    s_wifi_event_group = xEventGroupCreate();
+    s_retries = 0;
+
+    esp_event_handler_instance_t inst_any, inst_ip;
+    esp_event_handler_instance_register(WIFI_EVENT, ESP_EVENT_ANY_ID,    wifi_event_handler, NULL, &inst_any);
+    esp_event_handler_instance_register(IP_EVENT,   IP_EVENT_STA_GOT_IP, wifi_event_handler, NULL, &inst_ip);
+
+    wifi_config_t wifi_cfg = {};
+    strncpy((char*)wifi_cfg.sta.ssid,     CONFIG_ESP_WIFI_SSID,     sizeof(wifi_cfg.sta.ssid)     - 1);
+    strncpy((char*)wifi_cfg.sta.password, CONFIG_ESP_WIFI_PASSWORD, sizeof(wifi_cfg.sta.password) - 1);
+    wifi_cfg.sta.threshold.authmode = WIFI_AUTH_WPA2_PSK;
+
+    esp_wifi_set_mode(WIFI_MODE_STA);
+    esp_wifi_set_config(WIFI_IF_STA, &wifi_cfg);
+    esp_wifi_start();
+
+    EventBits_t bits = xEventGroupWaitBits(s_wifi_event_group, CONNECTED_BIT,
+                                           pdFALSE, pdFALSE, pdMS_TO_TICKS(30000));
+    if(!(bits & CONNECTED_BIT)) {
+        ESP_LOGW(TAG, "WiFi not connected after 30 s — continuing without network");
+    }
+
+    vEventGroupDelete(s_wifi_event_group);
+    s_wifi_event_group = NULL;
+}
+
+bool Networking::isConnected() const {
+    wifi_ap_record_t ap;
+    return esp_wifi_sta_get_ap_info(&ap) == ESP_OK;
+}

device/main/Networking.hpp

@@ -1,9 +1,10 @@
-#ifndef _NETWORKING_HPP
-#define _NETWORKING_HPP
+#pragma once
 
 class Networking {
-	public:
-		void connectWifi();
-};
+public:
+    /* Connects to the WiFi configured in Kconfig (CONFIG_ESP_WIFI_SSID / _PASSWORD).
+     * Blocks up to 30 s, then returns regardless of connection state. */
+    void connectWifi();
 
-#endif
+    bool isConnected() const;
+};

device/main/WebInterface.cpp

@@ -8,7 +8,7 @@
 #include <board.h>
 #include <periph_sdcard.h>
 #include <esp_system.h>
-#include <esp_wifi.h>
+#include <esp_netif.h>
 #include <fcntl.h>
 #include <errno.h>
 #include <string.h>

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();