fix(footer): stop generating collision-prone social-link ids, fragile track key

createSocialLinkRow derived the new id from the current array length
(social-${length+1}). Add/remove/add cycles reliably reproduce a duplicate
id: add,add -> social-1/social-2; remove social-1 -> array length 1; add
-> social-2 again, colliding with the surviving row. footer.component.html
tracks footer nav items by id (@for ... track item.id), so a duplicate id
there corrupts Angular's DOM reuse on the public storefront footer.

Also switched the payment-icon @for from track icon.src to track $index -
two icon rows sharing a src (most commonly two blank ones) hit the same bug.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

src/app/components/footer/footer.component.html

@@ -28,7 +28,7 @@
       <div class="app-footer__group">
         <h4>{{ 'footer.payment' | translate }}</h4>
         <div class="app-footer__payments">
-          @for (icon of paymentIcons(); track icon.src) {
+          @for (icon of paymentIcons(); track $index) {
             <img [src]="icon.src" [alt]="icon.alt" loading="lazy" [width]="icon.width" [height]="icon.height" />
           }
         </div>