Add homepage link for ESP CAN joystick controller project

[Copilot]

The site did not surface the ESP_CAN_ECU_joystick_collection repository, so the forwarder CAN joystick / hydraulic controller project was missing from the main project index. This update adds it to the homepage alongside the other AgOpenGPS-related tools and repositories.

• Homepage navigation

  • Added a new compact card to the main AgOpenGPS – Tudásbázis & eszközök section in index.html
  • Linked the card to https://github.com/gunicsba/ESP_CAN_ECU_joystick_collection

• Project metadata

  • Added focused tags for discoverability: esp32, can, joystick, j1939, hydraulic, forwarder
  • Added a short Hungarian description to match the surrounding homepage content

• UI consistency

  • Reused the existing compact card pattern so the new entry follows the current layout and styling without introducing new structure or CSS

<article class="card compact" data-tags="esp32 can joystick j1939 hydraulic forwarder">
  <a href="https://github.com/gunicsba/ESP_CAN_ECU_joystick_collection" target="_blank" rel="noopener">
    <div class="kicker">ESP32 / CAN</div>
    <div class="name">Forwarder CAN joystick ECU</div>
    <p>Nyílt forrású ESP32 CAN joystick és hidraulika vezérlő gyűjtemény forwarder géphez.</p>
  </a>
</article>