fix(project-editor): validate footer payment/social links, add footer logo picker

- header-section: raw checkboxes -> app-toggle, wrap in SectionCard
- footer-section: replace unvalidated pipe-delimited textareas for payment
  icons/social links with KeyValueEditor + MediaPickerComponent, add missing
  footer logo picker, validate social link URLs (http/https), wrap in SectionCard
- i18n: add footer logo / key-value-editor labels and URL validation message

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

src/app/features/project-editor/sections/header-section.component.html

@@ -1,14 +1,13 @@
 @if (bootstrap(); as bootstrap) {
-<section class="editor-section-card">
-  <h2>{{ 'builder.header' | translate }}</h2>
+<app-section-card [title]="'builder.header' | translate">
   <div class="editor-grid three toggles">
     @for (item of items; track item.key) {
       <label class="toggle-row">
-        <input type="checkbox" [checked]="isChecked(item.key)" (change)="toggle(item.key, $any($event.target).checked)" />
+        <app-toggle [ngModel]="isChecked(item.key)" (ngModelChange)="toggle(item.key, $event)" [ariaLabel]="item.label | translate" />
         <span>{{ item.label | translate }}</span>
         <small class="field-desc">{{ item.descKey | translate }}</small>
       </label>
     }
   </div>
-</section>
+</app-section-card>
 }