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/components/nfc_engine/jobs.c

@@ -0,0 +1,23 @@
+#include "nfc_engine/jobs.h"
+#include "esp_log.h"
+#include <string.h>
+
+static const char *TAG = "nfc_jobs";
+
+uint32_t jobs_create(const char *name)
+{
+    static uint32_t s_next = 1;
+    (void)name;
+    ESP_LOGI(TAG, "job %s id=%lu", name ? name : "?", (unsigned long)s_next);
+    return s_next++;
+}
+
+void jobs_set_progress(uint32_t id, int pct, const char *msg)
+{
+    ESP_LOGD(TAG, "job %lu %d%% %s", (unsigned long)id, pct, msg ? msg : "");
+}
+
+void jobs_finish(uint32_t id)
+{
+    ESP_LOGI(TAG, "job %lu done", (unsigned long)id);
+}