fw: robust HTTP body reads, CORS preflight, LED off at boot; update docs

- app_net.c: replace bare httpd_req_recv with recv_body_capped/alloc
  helpers (TCP-safe, full-body reads); add OPTIONS/* CORS preflight
  handler; bump WS broadcast buffer to 2048; add CORS Allow-Methods
- CMakeLists (net_service): add http_parser dep for HTTP_OPTIONS
- nfc_engine/pn532_core: add nfc_access_lock/unlock mutex, board-RGB
  quiet helper, UL type detection, general-status improvements
- pn532_transport: minor cleanup
- main.c: call board_rgb_led_quiet() at boot to kill onboard LED
- sdkconfig.defaults: add board RGB Kconfig defaults
- README, docs/LIMITATIONS, docs/PINOUT: expand and correct

Made-with: Cursor

firmware/components/nfc_engine/nfc_engine.c

@@ -18,7 +18,12 @@ static void hint_type(nfc_tag_info_t *t)
         t->type_hint = 1;
         break;
     case 0x00:
-        t->type_hint = 2;
+        /* Typical Type 2 inventory tuple is ATQA 0x0044 and 7-byte UID. */
+        if ((t->atqa == 0x4400 || t->atqa == 0x0044) && t->uid_len == 7) {
+            t->type_hint = 2;
+        } else {
+            t->type_hint = 0;
+        }
         break;
     default:
         t->type_hint = 0;
@@ -41,6 +46,45 @@ bool nfc_tag_is_type2(const nfc_tag_info_t *tag)
     return tag && tag->type_hint == 2;
 }
 
+int nfc_mifare_sector_count(const nfc_tag_info_t *tag)
+{
+    if (!nfc_tag_is_mifare_classic(tag)) {
+        return 0;
+    }
+    return nfc_tag_is_mifare_classic_4k(tag) ? 40 : 16;
+}
+
+bool nfc_mifare_sector_layout(const nfc_tag_info_t *tag, int sector, int *first_block, int *num_blocks,
+                              uint8_t *trailer_block)
+{
+    if (!nfc_tag_is_mifare_classic(tag) || !first_block || !num_blocks || !trailer_block) {
+        return false;
+    }
+    if (!nfc_tag_is_mifare_classic_4k(tag)) {
+        if (sector < 0 || sector > 15) {
+            return false;
+        }
+        *first_block = sector * 4;
+        *num_blocks = 4;
+        *trailer_block = (uint8_t)(sector * 4 + 3);
+        return true;
+    }
+    if (sector < 0 || sector > 39) {
+        return false;
+    }
+    if (sector <= 31) {
+        *first_block = sector * 4;
+        *num_blocks = 4;
+        *trailer_block = (uint8_t)(sector * 4 + 3);
+    } else {
+        int r = sector - 32;
+        *first_block = 128 + r * 16;
+        *num_blocks = 16;
+        *trailer_block = (uint8_t)(128 + r * 16 + 15);
+    }
+    return true;
+}
+
 esp_err_t nfc_engine_init(void)
 {
     esp_err_t e = pn532_core_init();
@@ -248,6 +292,25 @@ esp_err_t nfc_ul_fast_read(uint8_t start_page, uint8_t *out, size_t out_max, siz
     return ESP_OK;
 }
 
+esp_err_t nfc_type2_get_version(uint8_t version[8])
+{
+    if (!version) {
+        return ESP_ERR_INVALID_ARG;
+    }
+    uint8_t d[] = {0x60};
+    uint8_t resp[32];
+    size_t rlen = 0;
+    esp_err_t e = in_data_tg(d, sizeof(d), resp, sizeof(resp), &rlen);
+    if (e != ESP_OK) {
+        return e;
+    }
+    if (rlen < 2 + 8 || resp[0] != (uint8_t)(PN532_CMD_INDATAEXCHANGE + 1) || resp[1] != 0x00) {
+        return ESP_ERR_INVALID_RESPONSE;
+    }
+    memcpy(version, resp + 2, 8);
+    return ESP_OK;
+}
+
 cJSON *nfc_tag_to_json(const nfc_tag_info_t *tag)
 {
     if (!tag || tag->uid_len > NFC_MAX_UID_LEN) {