Add HardwareRfid class implementation and integrate with main loop

lib/hardware/hardware_rfid.cpp

@@ -0,0 +1,44 @@
+#include "hardware_rfid.hpp"
+#include <Arduino.h>
+
+HardwareRfid::HardwareRfid(uint8_t ssPin, uint8_t rstPin)
+    : _mfrc(ssPin, rstPin) {}
+
+void HardwareRfid::begin() {
+    _mfrc.PCD_Init();
+}
+
+void HardwareRfid::end() {
+    // Nothing special to do
+}
+
+void HardwareRfid::update() {
+    if (!_mfrc.PICC_IsNewCardPresent() || !_mfrc.PICC_ReadCardSerial()) {
+        return;
+    }
+
+    // Get the UID
+    uint32_t cardId = 0;
+    for (byte i = 0; i < _mfrc.uid.size; i++) {
+        cardId = (cardId << 8) | _mfrc.uid.uidByte[i];
+    }
+
+    // Create the message
+    hardware_SensorToControlMessage msg = {0};
+    msg.sensor_id = 0; // Assuming single sensor
+    msg.which_payload = hardware_SensorToControlMessage_rfid_reading_tag; // Assuming this is the tag
+    msg.payload.rfid_reading.card_id = cardId;
+
+    // Call the callback if set
+    if (_callback) {
+        _callback(msg);
+    }
+
+    // Halt the card
+    _mfrc.PICC_HaltA();
+    _mfrc.PCD_StopCrypto1();
+}
+
+void HardwareRfid::setCallback(RfidCallback cb) {
+    _callback = cb;
+}