Add footer and dynamic copyright year script

Added footer with copyright year and dynamic date script.

Author: JustinVerstijnen

index.html

@@ -37,7 +37,10 @@ <h1>Password Generator</h1>
             <button class="copy-btn" id="copyBtn"><strong>🗐 Copy</strong></button>
         </div>
     </div>
-
+<div class="footer"><a href="https://github.com/JustinVerstijnen/DNSMegaTool">&copy; <span id="copyright-year">2025</span> DNS MEGAtool by Justin Verstijnen</a></div>
+<script>
+  document.getElementById('copyright-year').textContent = new Date().getFullYear();
+</script>
 <script src="assets/script.js"></script>
 </body>
 </html>