Fix invalid HTML structure (unclosed <main>, orphan </footer>) on index, contact, shop pages (#162)

* Fix missing main/footer HTML structure in index, contact, shop pages

Agent-Logs-Url: https://github.com/DavidKRK/DavidKRK.github.io/sessions/22a9b0b3-0b65-40f6-8d32-31b6fb1f1905

Co-authored-by: DavidKRK <136035295+DavidKRK@users.noreply.github.com>

* Move social icons into footer in contact.html

Agent-Logs-Url: https://github.com/DavidKRK/DavidKRK.github.io/sessions/73fb46a3-65a6-497f-90fe-72daccefd627

Co-authored-by: DavidKRK <136035295+DavidKRK@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: DavidKRK <136035295+DavidKRK@users.noreply.github.com>

Author: Copilot

contact.html

@@ -145,6 +145,11 @@ <h1 class="main-title">David KRK</h1>
               </form>
             </div>
           </div>
+        </div>
+      </main>
+
+      <footer>
+        <div class="flex justify-center gap-6 mb-4">
           <a href="https://www.facebook.com/DavidKRKofficial" target="_blank" rel="noopener noreferrer" aria-label="Facebook"
              class="social-icon text-2xl md:text-3xl text-white"><i class="fab fa-facebook"></i></a>
           <a href="https://www.instagram.com/davidkrk/" target="_blank" rel="noopener noreferrer" aria-label="Instagram"

index.html

@@ -116,6 +116,9 @@ <h1 class="main-title">David KRK</h1>
                 src="https://player-widget.mixcloud.com/widget/iframe/?hide_cover=1&hide_artwork=1&autoplay=1&feed=%2FDavidKRK%2Fdavid-krk-life-good-techno-ep3%2F"
                 allow="autoplay; encrypted-media; fullscreen; idle-detection; speaker-selection; web-share"></iframe>
       </section>
+    </main>
+
+    <footer>
       <div class="flex justify-center gap-6 mb-4">
         <a href="https://www.facebook.com/DavidKRKofficial" target="_blank" rel="noopener noreferrer" aria-label="Facebook"
            class="social-icon text-2xl md:text-3xl text-white"><i class="fab fa-facebook"></i></a>

shop.html

@@ -177,6 +177,9 @@ <h2 class="mt-4">Офіційний магазин</h2>
           <img src="images/qr-tshirt-boutique.png" alt="QR‑код для замовлення офіційної футболки David KRK за 24,90 євро з доставкою">
         </div>
       </div>
+    </main>
+
+    <footer>
       <div class="flex justify-center gap-6 mb-4">
         <a href="https://www.facebook.com/DavidKRKofficial" target="_blank" rel="noopener noreferrer" aria-label="Facebook"
            class="social-icon text-2xl md:text-3xl text-white"><i class="fab fa-facebook"></i></a>