Add PN532 toolkit firmware, web UI, and embedded SPIFFS assets

Includes ESP-IDF NFC stack (deep capture, 4K Classic geometry, UL write API,
open SoftAP), React dashboard with live tag diagnostics, and docs. README
updated for APIs and lab Wi-Fi defaults.

Made-with: Cursor

firmware/main/CMakeLists.txt

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+idf_component_register(SRCS "main.c" "board_rgb_off.c" INCLUDE_DIRS "." REQUIRES net_service nfc_engine led_strip)
+
+spiffs_create_partition_image(storage ../data FLASH_IN_PROJECT)

firmware/main/Kconfig.projbuild

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+menu "Board indicators"
+
+config BOARD_RGB_LED_ENABLE
+    bool "Turn off onboard addressable RGB at boot (WS2812/SK6812)"
+    default y
+    help
+        ESP32-S3-DevKitC-1 v1.x typically uses one SK6812/WS2812 on GPIO 48.
+        Disable if your board has no addressable LED or uses a different data pin.
+
+config BOARD_RGB_LED_GPIO
+    int "Addressable LED data GPIO"
+    default 48
+    range 0 48
+    depends on BOARD_RGB_LED_ENABLE
+    help
+        Official DevKitC-1 v1.1: GPIO 48. Older notes sometimes cite GPIO 38 — set in menuconfig if needed.
+
+endmenu

firmware/main/board_rgb_off.c

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+#include "sdkconfig.h"
+#include "board_rgb_off.h"
+#include "esp_log.h"
+
+#if CONFIG_BOARD_RGB_LED_ENABLE
+#include "esp_err.h"
+#include "led_strip.h"
+#endif
+
+void board_rgb_led_quiet(void)
+{
+#if CONFIG_BOARD_RGB_LED_ENABLE
+    led_strip_handle_t strip = NULL;
+    const led_strip_config_t strip_config = {
+        .strip_gpio_num = CONFIG_BOARD_RGB_LED_GPIO,
+        .max_leds = 1,
+        .led_pixel_format = LED_PIXEL_FORMAT_GRB,
+        .led_model = LED_MODEL_WS2812,
+        .flags = {.invert_out = false},
+    };
+    const led_strip_rmt_config_t rmt_config = {
+        .clk_src = RMT_CLK_SRC_DEFAULT,
+        .resolution_hz = 10 * 1000 * 1000,
+        .flags = {.with_dma = false},
+    };
+    esp_err_t err = led_strip_new_rmt_device(&strip_config, &rmt_config, &strip);
+    if (err != ESP_OK) {
+        ESP_LOGW("board_rgb", "RGB init failed (%s), leaving LED as-is", esp_err_to_name(err));
+        return;
+    }
+    err = led_strip_clear(strip);
+    if (err != ESP_OK) {
+        ESP_LOGW("board_rgb", "RGB clear failed (%s)", esp_err_to_name(err));
+    }
+    led_strip_del(strip);
+#endif
+}

firmware/main/board_rgb_off.h

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+#pragma once
+
+/** One-shot: drive onboard WS2812/SK6812 to black, then release RMT. */
+void board_rgb_led_quiet(void);

firmware/main/idf_component.yml

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+## IDF Component Manager — addressable RGB (DevKitC-1)
+dependencies:
+  espressif/led_strip: "^2.5.5"

firmware/main/main.c

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+#include "esp_log.h"
+#include "board_rgb_off.h"
+#include "nfc_engine/nfc_engine.h"
+#include "nfc_engine/session_capture.h"
+#include "net_service/app_net.h"
+
+static const char *TAG = "main";
+
+void app_main(void)
+{
+    board_rgb_led_quiet();
+    ESP_LOGI(TAG, "PN532 NFC Toolkit starting");
+    ESP_ERROR_CHECK(nfc_engine_init());
+    session_capture_init();
+    ESP_ERROR_CHECK(app_net_init());
+    ESP_LOGI(TAG, "Open AP SSID PN532-Toolkit — http://192.168.4.1");
+}